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<button class="button is-small is-link">Go</button> </div> </div> </form> </div> </div> <ol class="breathe-horizontal" start="1"> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2312.04849">arXiv:2312.04849</a> <span> [<a href="https://arxiv.org/pdf/2312.04849">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> </div> <p class="title is-5 mathjax"> Low Resistance Ohmic Contact to P-type Monolayer WSe2 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Xie%2C+J">Jingxu Xie</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+Z">Zuocheng Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+H">Haodong Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Nagarajan%2C+V">Vikram Nagarajan</a>, <a href="/search/cond-mat?searchtype=author&query=Zhao%2C+W">Wenyu Zhao</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+H">Haleem Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Sanborn%2C+C">Collin Sanborn</a>, <a href="/search/cond-mat?searchtype=author&query=Qi%2C+R">Ruishi Qi</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+S">Sudi Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Kahn%2C+S">Salman Kahn</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Zettl%2C+A">Alex Zettl</a>, <a href="/search/cond-mat?searchtype=author&query=Crommie%2C+M">Michael Crommie</a>, <a href="/search/cond-mat?searchtype=author&query=Analytis%2C+J">James Analytis</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+F">Feng Wang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2312.04849v1-abstract-short" style="display: inline;"> Advanced microelectronics in the future may require semiconducting channel materials beyond silicon. Two-dimensional (2D) semiconductors, characterized by their atomically thin thickness, hold immense promise for high-performance electronic devices at the nanometer scale with lower heat dissipation. One challenge for achieving high-performance 2D semiconductor field effect transistors (FET), espec… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.04849v1-abstract-full').style.display = 'inline'; document.getElementById('2312.04849v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2312.04849v1-abstract-full" style="display: none;"> Advanced microelectronics in the future may require semiconducting channel materials beyond silicon. Two-dimensional (2D) semiconductors, characterized by their atomically thin thickness, hold immense promise for high-performance electronic devices at the nanometer scale with lower heat dissipation. One challenge for achieving high-performance 2D semiconductor field effect transistors (FET), especially for p-type materials, is the high electrical contact resistance present at the metal-semiconductor interface. In conventional bulk semiconductors, low resistance ohmic contact is realized through heavy substitutional doping with acceptor or donor impurities at the contact region. The strategy of substitutional doping, however, does not work for p-type 2D semiconductors such as monolayer tungsten diselenide (WSe$_2$).In this study, we developed highly efficient charge-transfer doping with WSe$_2$/$伪$-RuCl$_3$ heterostructures to achieve low-resistance ohmic contact for p-type WSe$_2$ transistors. We show that a hole doping as high as 3$\times$10$^{13}$ cm$^{-2}$ can be achieved in the WSe$_2/伪$-RuCl$_3$ heterostructure due to its type-III band alignment. It results in an Ohmic contact with resistance lower than 4 k Ohm $渭$m at the p-type monolayer WSe$_2$/metal junction. at room temperature. Using this low-resistance contact, we demonstrate high-performance p-type WSe$_2$ transistors with a saturation current of 35 $渭$A$\cdot$ $渭$m$^{-1}$ and an I$_{ON}$/I$_{OFF}$ ratio exceeding 10$^9$ It could enable future microelectronic devices based on 2D semiconductors and contribute to the extension of Moore's law. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.04849v1-abstract-full').style.display = 'none'; document.getElementById('2312.04849v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 December, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2308.15471">arXiv:2308.15471</a> <span> [<a href="https://arxiv.org/pdf/2308.15471">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Applied Physics">physics.app-ph</span> </div> </div> <p class="title is-5 mathjax"> Three-dimensional imaging of buried heterointerfaces </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=O%27Leary%2C+C+M">Colum M. O'Leary</a>, <a href="/search/cond-mat?searchtype=author&query=Sha%2C+H">Haozhi Sha</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+J">Jianhua Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Su%2C+C">Cong Su</a>, <a href="/search/cond-mat?searchtype=author&query=Kahn%2C+S">Salman Kahn</a>, <a href="/search/cond-mat?searchtype=author&query=Jiang%2C+H">Huaidong Jiang</a>, <a href="/search/cond-mat?searchtype=author&query=Zettl%2C+A">Alex Zettl</a>, <a href="/search/cond-mat?searchtype=author&query=Ciston%2C+J">Jim Ciston</a>, <a href="/search/cond-mat?searchtype=author&query=Miao%2C+J">Jianwei Miao</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2308.15471v3-abstract-short" style="display: inline;"> We report three-dimensional (3D) structure determination of a twisted hexagonal boron nitride (h-BN) heterointerface from a single-view data set using multislice ptychography. We identify the buried heterointerface between two twisted h-BN flakes with a lateral resolution of 0.57 脜 and a depth resolution of 2.5 nm. The latter is a significant improvement (~2.7 times) over the aperture-limited dept… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.15471v3-abstract-full').style.display = 'inline'; document.getElementById('2308.15471v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2308.15471v3-abstract-full" style="display: none;"> We report three-dimensional (3D) structure determination of a twisted hexagonal boron nitride (h-BN) heterointerface from a single-view data set using multislice ptychography. We identify the buried heterointerface between two twisted h-BN flakes with a lateral resolution of 0.57 脜 and a depth resolution of 2.5 nm. The latter is a significant improvement (~2.7 times) over the aperture-limited depth resolution of incoherent imaging modes such as annular-dark-field scanning transmission electron microscopy. This is attributed to the diffraction signal extending beyond the aperture edge with the depth resolution set by the curvature of the Ewald sphere. Future advances to this approach could improve the depth resolution to the sub-nanometer level and enable the identification of individual dopants, defects and color centers in twisted heterointerfaces and other materials. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.15471v3-abstract-full').style.display = 'none'; document.getElementById('2308.15471v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 29 August, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2212.03380">arXiv:2212.03380</a> <span> [<a href="https://arxiv.org/pdf/2212.03380">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> </div> <p class="title is-5 mathjax"> Visualizing and manipulating chiral interface states in a moir茅 quantum anomalous Hall insulator </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+C">Canxun Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Zhu%2C+T">Tiancong Zhu</a>, <a href="/search/cond-mat?searchtype=author&query=Kahn%2C+S">Salman Kahn</a>, <a href="/search/cond-mat?searchtype=author&query=Soejima%2C+T">Tomohiro Soejima</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Zettl%2C+A">Alex Zettl</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+F">Feng Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Zaletel%2C+M+P">Michael P. Zaletel</a>, <a href="/search/cond-mat?searchtype=author&query=Crommie%2C+M+F">Michael F. Crommie</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2212.03380v2-abstract-short" style="display: inline;"> Moir茅 systems made from stacked two-dimensional materials host novel correlated and topological states that can be electrically controlled via applied gate voltages. We have used this technique to manipulate Chern domains in an interaction-driven quantum anomalous Hall insulator made from twisted monolayer-bilayer graphene (tMBLG). This has allowed the wavefunction of chiral interface states to be… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2212.03380v2-abstract-full').style.display = 'inline'; document.getElementById('2212.03380v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2212.03380v2-abstract-full" style="display: none;"> Moir茅 systems made from stacked two-dimensional materials host novel correlated and topological states that can be electrically controlled via applied gate voltages. We have used this technique to manipulate Chern domains in an interaction-driven quantum anomalous Hall insulator made from twisted monolayer-bilayer graphene (tMBLG). This has allowed the wavefunction of chiral interface states to be directly imaged using a scanning tunneling microscope (STM). To accomplish this tMBLG carrier concentration was tuned to stabilize neighboring domains of opposite Chern number, thus providing topological interfaces completely devoid of any structural boundaries. STM tip pulse-induced quantum dots were utilized to induce new Chern domains and thereby create new chiral interface states with tunable chirality at predetermined locations. Theoretical analysis confirms the chiral nature of observed interface states and enables the determination of the characteristic length scale of valley polarization reversal across neighboring tMBLG Chern domains. tMBLG is shown to be a useful platform for imaging the exotic topological properties of correlated moir茅 systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2212.03380v2-abstract-full').style.display = 'none'; document.getElementById('2212.03380v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 July, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 6 December, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">30 pages, 13 figures, 1 table</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2210.06506">arXiv:2210.06506</a> <span> [<a href="https://arxiv.org/pdf/2210.06506">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41467-023-39110-3">10.1038/s41467-023-39110-3 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Local spectroscopy of a gate-switchable moir茅 quantum anomalous Hall insulator </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+C">Canxun Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Zhu%2C+T">Tiancong Zhu</a>, <a href="/search/cond-mat?searchtype=author&query=Soejima%2C+T">Tomohiro Soejima</a>, <a href="/search/cond-mat?searchtype=author&query=Kahn%2C+S">Salman Kahn</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Zettl%2C+A">Alex Zettl</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+F">Feng Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Zaletel%2C+M+P">Michael P. Zaletel</a>, <a href="/search/cond-mat?searchtype=author&query=Crommie%2C+M+F">Michael F. Crommie</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2210.06506v2-abstract-short" style="display: inline;"> In recent years, correlated insulating states, unconventional superconductivity, and topologically non-trivial phases have all been observed in several moir茅 heterostructures. However, understanding of the physical mechanisms behind these phenomena is hampered by the lack of local electronic structure data. Here, we use scanning tunnelling microscopy and spectroscopy to demonstrate how the interpl… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.06506v2-abstract-full').style.display = 'inline'; document.getElementById('2210.06506v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2210.06506v2-abstract-full" style="display: none;"> In recent years, correlated insulating states, unconventional superconductivity, and topologically non-trivial phases have all been observed in several moir茅 heterostructures. However, understanding of the physical mechanisms behind these phenomena is hampered by the lack of local electronic structure data. Here, we use scanning tunnelling microscopy and spectroscopy to demonstrate how the interplay between correlation, topology, and local atomic structure determines the behaviour of electron-doped twisted monolayer-bilayer graphene. Through gate- and magnetic field-dependent measurements, we observe local spectroscopic signatures indicating a quantum anomalous Hall insulating state with a total Chern number of $\pm 2$ at a doping level of three electrons per moir茅 unit cell. We show that the sign of the Chern number and associated magnetism can be electrostatically switched only over a limited range of twist angle and sample hetero-strain values. This results from a competition between the orbital magnetization of filled bulk bands and chiral edge states, which is sensitive to strain-induced distortions in the moir茅 superlattice. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.06506v2-abstract-full').style.display = 'none'; document.getElementById('2210.06506v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 May, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 12 October, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Article 14 pages, 4 figures & Supplementary Information 13 pages, 9 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Communications 14, 3595 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2207.05938">arXiv:2207.05938</a> <span> [<a href="https://arxiv.org/pdf/2207.05938">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Quantum Physics">quant-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1021/acs.nanolett.1c02271">10.1021/acs.nanolett.1c02271 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Imaging Quantum Interference in Stadium-Shaped Monolayer and Bilayer Graphene Quantum Dots </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Ge%2C+Z">Zhehao Ge</a>, <a href="/search/cond-mat?searchtype=author&query=Wong%2C+D">Dillon Wong</a>, <a href="/search/cond-mat?searchtype=author&query=Lee%2C+J">Juwon Lee</a>, <a href="/search/cond-mat?searchtype=author&query=Joucken%2C+F">Frederic Joucken</a>, <a href="/search/cond-mat?searchtype=author&query=Quezada-Lopez%2C+E+A">Eberth A. Quezada-Lopez</a>, <a href="/search/cond-mat?searchtype=author&query=Kahn%2C+S">Salman Kahn</a>, <a href="/search/cond-mat?searchtype=author&query=Tsai%2C+H">Hsin-Zon Tsai</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+F">Feng Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Zettl%2C+A">Alex Zettl</a>, <a href="/search/cond-mat?searchtype=author&query=Crommie%2C+M+F">Michael F. Crommie</a>, <a href="/search/cond-mat?searchtype=author&query=Velasco%2C+J">Jairo Velasco Jr</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2207.05938v1-abstract-short" style="display: inline;"> Experimental realization of graphene-based stadium-shaped quantum dots (QDs) have been few and incompatible with scanned probe microscopy. Yet, direct visualization of electronic states within these QDs is crucial for determining the existence of quantum chaos in these systems. We report the fabrication and characterization of electrostatically defined stadium-shaped QDs in heterostructure devices… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.05938v1-abstract-full').style.display = 'inline'; document.getElementById('2207.05938v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2207.05938v1-abstract-full" style="display: none;"> Experimental realization of graphene-based stadium-shaped quantum dots (QDs) have been few and incompatible with scanned probe microscopy. Yet, direct visualization of electronic states within these QDs is crucial for determining the existence of quantum chaos in these systems. We report the fabrication and characterization of electrostatically defined stadium-shaped QDs in heterostructure devices composed of monolayer graphene (MLG) and bilayer graphene (BLG). To realize a stadium-shaped QD, we utilized the tip of a scanning tunneling microscope to charge defects in a supporting hexagonal boron nitride flake. The stadium states visualized are consistent with tight-binding-based simulations, but lack clear quantum chaos signatures. The absence of quantum chaos features in MLG-based stadium QDs is attributed to the leaky nature of the confinement potential due to Klein tunneling. In contrast, for BLG-based stadium QDs (which have stronger confinement) quantum chaos is precluded by the smooth confinement potential which reduces interference and mixing between states. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.05938v1-abstract-full').style.display = 'none'; document.getElementById('2207.05938v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 July, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nano Letters 2021 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2205.13126">arXiv:2205.13126</a> <span> [<a href="https://arxiv.org/pdf/2205.13126">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.106.075153">10.1103/PhysRevB.106.075153 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observation of a multitude of correlated states at the surface of bulk 1T-TaSe$_2$ crystals </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Chen%2C+Y">Yi Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Ruan%2C+W">Wei Ruan</a>, <a href="/search/cond-mat?searchtype=author&query=Cain%2C+J+D">Jeffrey D. Cain</a>, <a href="/search/cond-mat?searchtype=author&query=Lee%2C+R+L">Ryan L. Lee</a>, <a href="/search/cond-mat?searchtype=author&query=Kahn%2C+S">Salman Kahn</a>, <a href="/search/cond-mat?searchtype=author&query=Jia%2C+C">Caihong Jia</a>, <a href="/search/cond-mat?searchtype=author&query=Zettl%2C+A">Alex Zettl</a>, <a href="/search/cond-mat?searchtype=author&query=Crommie%2C+M+F">Michael F. Crommie</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2205.13126v2-abstract-short" style="display: inline;"> The interplay between electron-electron interactions and structural ordering can yield exceptionally rich correlated electronic phases. We have used scanning tunneling microscopy to investigate bulk 1T-TaSe2 and have uncovered surprisingly diverse correlated surface states thereof. These surface states exhibit the same in-plane charge density wave ordering but dramatically different electronic gro… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2205.13126v2-abstract-full').style.display = 'inline'; document.getElementById('2205.13126v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2205.13126v2-abstract-full" style="display: none;"> The interplay between electron-electron interactions and structural ordering can yield exceptionally rich correlated electronic phases. We have used scanning tunneling microscopy to investigate bulk 1T-TaSe2 and have uncovered surprisingly diverse correlated surface states thereof. These surface states exhibit the same in-plane charge density wave ordering but dramatically different electronic ground states ranging from insulating to metallic. The insulating variety of surface state shows signatures of a decoupled surface Mott layer. The metallic surface states, on the other hand, exhibit zero-bias peaks of varying strength that suggest Kondo phases arising from coupling between the Mott surface layer and the metallic bulk of 1T-TaSe2. The surface of bulk 1T-TaSe2 thus constitutes a rare realization of the periodic Anderson model covering a wide parameter regime, thereby providing a model system for accessing different correlated phenomena in the same crystal. Our results highlight the central role played by strong correlations in this material family. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2205.13126v2-abstract-full').style.display = 'none'; document.getElementById('2205.13126v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 September, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 25 May, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 106, 075153 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2204.08157">arXiv:2204.08157</a> <span> [<a href="https://arxiv.org/pdf/2204.08157">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> </div> <p class="title is-5 mathjax"> Deep Learning Coherent Diffractive Imaging </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Chang%2C+D+J">Dillan J. Chang</a>, <a href="/search/cond-mat?searchtype=author&query=O%27Leary%2C+C+M">Colum M. O'Leary</a>, <a href="/search/cond-mat?searchtype=author&query=Su%2C+C">Cong Su</a>, <a href="/search/cond-mat?searchtype=author&query=Kahn%2C+S">Salman Kahn</a>, <a href="/search/cond-mat?searchtype=author&query=Zettl%2C+A">Alex Zettl</a>, <a href="/search/cond-mat?searchtype=author&query=Ciston%2C+J">Jim Ciston</a>, <a href="/search/cond-mat?searchtype=author&query=Ercius%2C+P">Peter Ercius</a>, <a href="/search/cond-mat?searchtype=author&query=Miao%2C+J">Jianwei Miao</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2204.08157v1-abstract-short" style="display: inline;"> We report the development of deep learning coherent electron diffractive imaging at sub-angstrom resolution using convolutional neural networks (CNNs) trained with only simulated data. We experimentally demonstrate this method by applying the trained CNNs to directly recover the phase images from electron diffraction patterns of twisted hexagonal boron nitride, monolayer graphene and a Au nanopart… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.08157v1-abstract-full').style.display = 'inline'; document.getElementById('2204.08157v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2204.08157v1-abstract-full" style="display: none;"> We report the development of deep learning coherent electron diffractive imaging at sub-angstrom resolution using convolutional neural networks (CNNs) trained with only simulated data. We experimentally demonstrate this method by applying the trained CNNs to directly recover the phase images from electron diffraction patterns of twisted hexagonal boron nitride, monolayer graphene and a Au nanoparticle with comparable quality to those reconstructed by a conventional ptychographic method. Fourier ring correlation between the CNN and ptychographic images indicates the achievement of a spatial resolution in the range of 0.70 and 0.55 angstrom (depending on different resolution criteria). The ability to replace iterative algorithms with CNNs and perform real-time imaging from coherent diffraction patterns is expected to find broad applications in the physical and biological sciences. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.08157v1-abstract-full').style.display = 'none'; document.getElementById('2204.08157v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 April, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">19 pages, 7 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2108.04747">arXiv:2108.04747</a> <span> [<a href="https://arxiv.org/pdf/2108.04747">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> </div> <p class="title is-5 mathjax"> Tuning color centers at a twisted interface </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Su%2C+C">Cong Su</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+F">Fang Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Kahn%2C+S">Salman Kahn</a>, <a href="/search/cond-mat?searchtype=author&query=Shevitski%2C+B">Brian Shevitski</a>, <a href="/search/cond-mat?searchtype=author&query=Jiang%2C+J">Jingwei Jiang</a>, <a href="/search/cond-mat?searchtype=author&query=Dai%2C+C">Chunhui Dai</a>, <a href="/search/cond-mat?searchtype=author&query=Ungar%2C+A">Alex Ungar</a>, <a href="/search/cond-mat?searchtype=author&query=Park%2C+J">Ji-Hoon Park</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Kong%2C+J">Jing Kong</a>, <a href="/search/cond-mat?searchtype=author&query=Tang%2C+Z">Zikang Tang</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+W">Wenqing Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+F">Feng Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Crommie%2C+M">Michael Crommie</a>, <a href="/search/cond-mat?searchtype=author&query=Louie%2C+S+G">Steven G. Louie</a>, <a href="/search/cond-mat?searchtype=author&query=Aloni%2C+S">Shaul Aloni</a>, <a href="/search/cond-mat?searchtype=author&query=Zettl%2C+A">Alex Zettl</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2108.04747v1-abstract-short" style="display: inline;"> Color center is a promising platform for quantum technologies, but their application is hindered by the typically random defect distribution and complex mesoscopic environment. Employing cathodoluminescence, we demonstrate that an ultraviolet-emitting single photon emitter can be readily activated and controlled on-demand at the twisted interface of two hexagonal boron nitride flakes. The brightne… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2108.04747v1-abstract-full').style.display = 'inline'; document.getElementById('2108.04747v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2108.04747v1-abstract-full" style="display: none;"> Color center is a promising platform for quantum technologies, but their application is hindered by the typically random defect distribution and complex mesoscopic environment. Employing cathodoluminescence, we demonstrate that an ultraviolet-emitting single photon emitter can be readily activated and controlled on-demand at the twisted interface of two hexagonal boron nitride flakes. The brightness of the color center can be enhanced by two orders of magnitude by altering the twist angle. Additionally, a brightness modulation of nearly 100% of this color center is achieved by an external voltage. Our ab-initio GW calculations suggest that the emission is correlated to nitrogen vacancies and that a twist-induced moir茅 potential facilitates electron-hole recombination. This mechanism is further exploited to draw nanoscale color center patterns using electron beams. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2108.04747v1-abstract-full').style.display = 'none'; document.getElementById('2108.04747v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 August, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2021. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2106.10599">arXiv:2106.10599</a> <span> [<a href="https://arxiv.org/pdf/2106.10599">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> </div> <p class="title is-5 mathjax"> Imaging Generalized Wigner Crystal States in a WSe2/WS2 Moir茅 Superlattice </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Li%2C+H">Hongyuan Li</a>, <a href="/search/cond-mat?searchtype=author&query=Li%2C+S">Shaowei Li</a>, <a href="/search/cond-mat?searchtype=author&query=Regan%2C+E+C">Emma C. Regan</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+D">Danqing Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Zhao%2C+W">Wenyu Zhao</a>, <a href="/search/cond-mat?searchtype=author&query=Kahn%2C+S">Salman Kahn</a>, <a href="/search/cond-mat?searchtype=author&query=Yumigeta%2C+K">Kentaro Yumigeta</a>, <a href="/search/cond-mat?searchtype=author&query=Blei%2C+M">Mark Blei</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Tongay%2C+S">Sefaattin Tongay</a>, <a href="/search/cond-mat?searchtype=author&query=Zettl%2C+A">Alex Zettl</a>, <a href="/search/cond-mat?searchtype=author&query=Crommie%2C+M+F">Michael F. Crommie</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+F">Feng Wang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2106.10599v1-abstract-short" style="display: inline;"> The Wigner crystal state, first predicted by Eugene Wigner in 1934, has fascinated condensed matter physicists for nearly 90 years2-14. Studies of two-dimensional (2D) electron gases first revealed signatures of the Wigner crystal in electrical transport measurements at high magnetic fields2-4. More recently optical spectroscopy has provided evidence of generalized Wigner crystal states in transit… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.10599v1-abstract-full').style.display = 'inline'; document.getElementById('2106.10599v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2106.10599v1-abstract-full" style="display: none;"> The Wigner crystal state, first predicted by Eugene Wigner in 1934, has fascinated condensed matter physicists for nearly 90 years2-14. Studies of two-dimensional (2D) electron gases first revealed signatures of the Wigner crystal in electrical transport measurements at high magnetic fields2-4. More recently optical spectroscopy has provided evidence of generalized Wigner crystal states in transition metal dichalcogenide (TMDC) moir茅 superlattices. Direct observation of the 2D Wigner crystal lattice in real space, however, has remained an outstanding challenge. Scanning tunneling microscopy (STM) in principle has sufficient spatial resolution to image a Wigner crystal, but conventional STM measurements can potentially alter fragile Wigner crystal states in the process of measurement. Here we demonstrate real-space imaging of 2D Wigner crystals in WSe2/WS2 moir茅 heterostructures using a novel non-invasive STM spectroscopy technique. We employ a graphene sensing layer in close proximity to the WSe2/WS2 moir茅 superlattice for Wigner crystal imaging, where local STM tunneling current into the graphene sensing layer is modulated by the underlying electron lattice of the Wigner crystal in the WSe2/WS2 heterostructure. Our measurement directly visualizes different lattice configurations associated with Wigner crystal states at fractional electron fillings of n = 1/3, 1/2, and 2/3, where n is the electron number per site. The n=1/3 and n=2/3 Wigner crystals are observed to exhibit a triangle and a honeycomb lattice, respectively, in order to minimize nearest-neighbor occupations. The n = 1/2 state, on the other hand, spontaneously breaks the original C3 symmetry and forms a stripe structure in real space. Our study lays a solid foundation toward the fundamental understanding of rich Wigner crystal states in WSe2/WS2 moir茅 heterostructures. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.10599v1-abstract-full').style.display = 'none'; document.getElementById('2106.10599v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 June, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2021. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2106.02021">arXiv:2106.02021</a> <span> [<a href="https://arxiv.org/pdf/2106.02021">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Optics">physics.optics</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Applied Physics">physics.app-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41586-021-03574-4">10.1038/s41586-021-03574-4 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Efficient Fizeau Drag from Dirac electrons in monolayer graphene </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Zhao%2C+W">Wenyu Zhao</a>, <a href="/search/cond-mat?searchtype=author&query=Zhao%2C+S">Sihan Zhao</a>, <a href="/search/cond-mat?searchtype=author&query=Li%2C+H">Hongyuan Li</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+S">Sheng Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+S">Shaoxin Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Utama%2C+M+I+B">M. Iqbal Bakti Utama</a>, <a href="/search/cond-mat?searchtype=author&query=Kahn%2C+S">Salman Kahn</a>, <a href="/search/cond-mat?searchtype=author&query=Jiang%2C+Y">Yue Jiang</a>, <a href="/search/cond-mat?searchtype=author&query=Xiao%2C+X">Xiao Xiao</a>, <a href="/search/cond-mat?searchtype=author&query=Yoo%2C+S">SeokJae Yoo</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Zettl%2C+A">Alex Zettl</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+F">Feng Wang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2106.02021v1-abstract-short" style="display: inline;"> Fizeau demonstrated in 1850 that the speed of light can be modified when it is propagating in moving media. Can we achieve such control of the light speed efficiently with a fast-moving electron media by passing electrical current? Because the strong electromagnetic coupling between the electron and light leads to the collective excitation of plasmon polaritons, it will manifest as the plasmonic D… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.02021v1-abstract-full').style.display = 'inline'; document.getElementById('2106.02021v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2106.02021v1-abstract-full" style="display: none;"> Fizeau demonstrated in 1850 that the speed of light can be modified when it is propagating in moving media. Can we achieve such control of the light speed efficiently with a fast-moving electron media by passing electrical current? Because the strong electromagnetic coupling between the electron and light leads to the collective excitation of plasmon polaritons, it will manifest as the plasmonic Doppler effect. Experimental observation of the plasmonic Doppler effect in electronic system has been challenge because the plasmon propagation speed is much faster than the electron drift velocity in conventional noble metals. Here, we report direct observation of Fizeau drag of plasmon polaritons in strongly biased graphene by exploiting the high electron mobility and the slow plasmon propagation of massless Dirac electrons. The large bias current in graphene creates a fast drifting Dirac electron medium hosting the plasmon polariton. It results in nonreciprocal plasmon propagation, where plasmons moving with the drifting electron media propagate at an enhanced speed. We measure the Doppler-shifted plasmon wavelength using a cryogenic near-field infrared nanoscopy, which directly images the plasmon polariton mode in the biased graphene at low temperature. We observe a plasmon wavelength difference up to 3.6% between plasmon moving along and against the drifting electron media. Our findings on the plasmonic Doppler effect open new opportunities for electrical control of non-reciprocal surface plasmon polaritons in nonequilibrium systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.02021v1-abstract-full').style.display = 'none'; document.getElementById('2106.02021v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 3 June, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">31 pages, 11 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2009.07379">arXiv:2009.07379</a> <span> [<a href="https://arxiv.org/pdf/2009.07379">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41567-021-01321-0">10.1038/s41567-021-01321-0 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Imaging spinon density modulations in a 2D quantum spin liquid </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Ruan%2C+W">Wei Ruan</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+Y">Yi Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Tang%2C+S">Shujie Tang</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+J">Jinwoong Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Tsai%2C+H">Hsin-Zon Tsai</a>, <a href="/search/cond-mat?searchtype=author&query=Lee%2C+R">Ryan Lee</a>, <a href="/search/cond-mat?searchtype=author&query=Wu%2C+M">Meng Wu</a>, <a href="/search/cond-mat?searchtype=author&query=Ryu%2C+H">Hyejin Ryu</a>, <a href="/search/cond-mat?searchtype=author&query=Kahn%2C+S">Salman Kahn</a>, <a href="/search/cond-mat?searchtype=author&query=Liou%2C+F">Franklin Liou</a>, <a href="/search/cond-mat?searchtype=author&query=Jia%2C+C">Caihong Jia</a>, <a href="/search/cond-mat?searchtype=author&query=Aikawa%2C+A">Andrew Aikawa</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+C">Choongyu Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+F">Feng Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Choi%2C+Y">Yongseong Choi</a>, <a href="/search/cond-mat?searchtype=author&query=Louie%2C+S+G">Steven G. Louie</a>, <a href="/search/cond-mat?searchtype=author&query=Lee%2C+P+A">Patrick A. Lee</a>, <a href="/search/cond-mat?searchtype=author&query=Shen%2C+Z">Zhi-Xun Shen</a>, <a href="/search/cond-mat?searchtype=author&query=Mo%2C+S">Sung-Kwan Mo</a>, <a href="/search/cond-mat?searchtype=author&query=Crommie%2C+M+F">Michael F. Crommie</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2009.07379v1-abstract-short" style="display: inline;"> Two-dimensional triangular-lattice antiferromagnets are predicted under some conditions to exhibit a quantum spin liquid ground state whose low-energy behavior is described by a spinon Fermi surface. Directly imaging the resulting spinons, however, is difficult due to their fractional, chargeless nature. Here we use scanning tunneling spectroscopy to image spinon density modulations arising from a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.07379v1-abstract-full').style.display = 'inline'; document.getElementById('2009.07379v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2009.07379v1-abstract-full" style="display: none;"> Two-dimensional triangular-lattice antiferromagnets are predicted under some conditions to exhibit a quantum spin liquid ground state whose low-energy behavior is described by a spinon Fermi surface. Directly imaging the resulting spinons, however, is difficult due to their fractional, chargeless nature. Here we use scanning tunneling spectroscopy to image spinon density modulations arising from a spinon Fermi surface instability in single-layer 1T-TaSe$_2$, a two-dimensional Mott insulator. We first demonstrate the existence of localized spins arranged on a triangular lattice in single-layer 1T-TaSe$_2$ by contacting it to a metallic 1H-TaSe$_2$ layer and measuring the Kondo effect. Subsequent spectroscopic imaging of isolated, single-layer 1T-TaSe$_2$ reveals long-wavelength modulations at Hubbard band energies that reflect spinon density modulations. This allows direct experimental measurement of the spinon Fermi wavevector, in good agreement with theoretical predictions for a 2D quantum spin liquid. These results establish single-layer 1T-TaSe$_2$ as a new platform for studying novel two-dimensional quantum-spin-liquid phenomena. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.07379v1-abstract-full').style.display = 'none'; document.getElementById('2009.07379v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 September, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2020. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2008.07536">arXiv:2008.07536</a> <span> [<a href="https://arxiv.org/pdf/2008.07536">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41467-021-22711-1">10.1038/s41467-021-22711-1 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Visualizing delocalized correlated electronic states in twisted double bilayer graphene </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+C">Canxun Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Zhu%2C+T">Tiancong Zhu</a>, <a href="/search/cond-mat?searchtype=author&query=Kahn%2C+S">Salman Kahn</a>, <a href="/search/cond-mat?searchtype=author&query=Li%2C+S">Shaowei Li</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+B">Birui Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Herbig%2C+C">Charlotte Herbig</a>, <a href="/search/cond-mat?searchtype=author&query=Wu%2C+X">Xuehao Wu</a>, <a href="/search/cond-mat?searchtype=author&query=Li%2C+H">Hongyuan Li</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Cabrini%2C+S">Stefano Cabrini</a>, <a href="/search/cond-mat?searchtype=author&query=Zettl%2C+A">Alex Zettl</a>, <a href="/search/cond-mat?searchtype=author&query=Zaletel%2C+M+P">Michael P. Zaletel</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+F">Feng Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Crommie%2C+M+F">Michael F. Crommie</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2008.07536v2-abstract-short" style="display: inline;"> The discovery of interaction-driven insulating and superconducting phases in moir茅 van der Waals heterostructures has sparked considerable interest in understanding the novel correlated physics of these systems. While a significant number of studies have focused on twisted bilayer graphene, correlated insulating states and a superconductivity-like transition up to 12 K have been reported in recent… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2008.07536v2-abstract-full').style.display = 'inline'; document.getElementById('2008.07536v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2008.07536v2-abstract-full" style="display: none;"> The discovery of interaction-driven insulating and superconducting phases in moir茅 van der Waals heterostructures has sparked considerable interest in understanding the novel correlated physics of these systems. While a significant number of studies have focused on twisted bilayer graphene, correlated insulating states and a superconductivity-like transition up to 12 K have been reported in recent transport measurements of twisted double bilayer graphene. Here we present a scanning tunneling microscopy and spectroscopy study of gate-tunable twisted double bilayer graphene devices. We observe splitting of the van Hove singularity peak by ~20 meV at half-filling of the conduction flat band, with a corresponding reduction of the local density of states at the Fermi level. By mapping the tunneling differential conductance we show that this correlated system exhibits energetically split states that are spatially delocalized throughout the different regions in the moir茅 unit cell, inconsistent with order originating solely from onsite Coulomb repulsion within strongly-localized orbitals. We have performed self-consistent Hartree-Fock calculations that suggest exchange-driven spontaneous symmetry breaking in the degenerate conduction flat band is the origin of the observed correlated state. Our results provide new insight into the nature of electron-electron interactions in twisted double bilayer graphene and related moir茅 systems. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2008.07536v2-abstract-full').style.display = 'none'; document.getElementById('2008.07536v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 March, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 17 August, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">24 pages, 5 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Communications 12, 2516 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2007.06113">arXiv:2007.06113</a> <span> [<a href="https://arxiv.org/pdf/2007.06113">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41563-021-00923-6">10.1038/s41563-021-00923-6 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Imaging moir茅 flat bands in 3D reconstructed WSe2/WS2 superlattices </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Li%2C+H">Hongyuan Li</a>, <a href="/search/cond-mat?searchtype=author&query=Li%2C+S">Shaowei Li</a>, <a href="/search/cond-mat?searchtype=author&query=Naik%2C+M+H">Mit H. Naik</a>, <a href="/search/cond-mat?searchtype=author&query=Xie%2C+J">Jingxu Xie</a>, <a href="/search/cond-mat?searchtype=author&query=Li%2C+X">Xinyu Li</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+J">Jiayin Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Regan%2C+E">Emma Regan</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+D">Danqing Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Zhao%2C+W">Wenyu Zhao</a>, <a href="/search/cond-mat?searchtype=author&query=Zhao%2C+S">Sihan Zhao</a>, <a href="/search/cond-mat?searchtype=author&query=Kahn%2C+S">Salman Kahn</a>, <a href="/search/cond-mat?searchtype=author&query=Yumigeta%2C+K">Kentaro Yumigeta</a>, <a href="/search/cond-mat?searchtype=author&query=Blei%2C+M">Mark Blei</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Tongay%2C+S">Sefaattin Tongay</a>, <a href="/search/cond-mat?searchtype=author&query=Zettl%2C+A">Alex Zettl</a>, <a href="/search/cond-mat?searchtype=author&query=Louie%2C+S+G">Steven G. Louie</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+F">Feng Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Crommie%2C+M+F">Michael F. Crommie</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2007.06113v1-abstract-short" style="display: inline;"> Moir茅 superlattices in transition metal dichalcogenide (TMD) heterostructures can host novel correlated quantum phenomena due to the interplay of narrow moir茅 flat bands and strong, long-range Coulomb interactions1-5. However, microscopic knowledge of the atomically-reconstructed moir茅 superlattice and resulting flat bands is still lacking, which is critical for fundamental understanding and contr… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2007.06113v1-abstract-full').style.display = 'inline'; document.getElementById('2007.06113v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2007.06113v1-abstract-full" style="display: none;"> Moir茅 superlattices in transition metal dichalcogenide (TMD) heterostructures can host novel correlated quantum phenomena due to the interplay of narrow moir茅 flat bands and strong, long-range Coulomb interactions1-5. However, microscopic knowledge of the atomically-reconstructed moir茅 superlattice and resulting flat bands is still lacking, which is critical for fundamental understanding and control of the correlated moir茅 phenomena. Here we quantitatively study the moir茅 flat bands in three-dimensional (3D) reconstructed WSe2/WS2 moir茅 superlattices by comparing scanning tunneling spectroscopy (STS) of high quality exfoliated TMD heterostructure devices with ab initio simulations of TMD moir茅 superlattices. A strong 3D buckling reconstruction accompanied by large in-plane strain redistribution is identified in our WSe2/WS2 moir茅 heterostructures. STS imaging demonstrates that this results in a remarkably narrow and highly localized K-point moir茅 flat band at the valence band edge of the heterostructure. A series of moir茅 flat bands are observed at different energies that exhibit varying degrees of localization. Our observations contradict previous simplified theoretical models but agree quantitatively with ab initio simulations that fully capture the 3D structural reconstruction. Here the strain redistribution and 3D buckling dominate the effective moir茅 potential and result in moir茅 flat bands at the Brillouin zone K points. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2007.06113v1-abstract-full').style.display = 'none'; document.getElementById('2007.06113v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 July, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2020. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2006.04000">arXiv:2006.04000</a> <span> [<a href="https://arxiv.org/pdf/2006.04000">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1126/sciadv.abd1919">10.1126/sciadv.abd1919 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Ultra-high-resolution imaging of moir茅 lattices and superstructures using scanning microwave impedance microscopy under ambient conditions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Lee%2C+K">Kyunghoon Lee</a>, <a href="/search/cond-mat?searchtype=author&query=Utama%2C+M+I+B">M. Iqbal Bakti Utama</a>, <a href="/search/cond-mat?searchtype=author&query=Kahn%2C+S">Salman Kahn</a>, <a href="/search/cond-mat?searchtype=author&query=Samudrala%2C+A">Appalakondaiah Samudrala</a>, <a href="/search/cond-mat?searchtype=author&query=Leconte%2C+N">Nicolas Leconte</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+B">Birui Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+S">Shuopei Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+G">Guangyu Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Weber-Bargioni%2C+A">Alexander Weber-Bargioni</a>, <a href="/search/cond-mat?searchtype=author&query=Crommie%2C+M">Michael Crommie</a>, <a href="/search/cond-mat?searchtype=author&query=Ashby%2C+P+D">Paul D. Ashby</a>, <a href="/search/cond-mat?searchtype=author&query=Jung%2C+J">Jeil Jung</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+F">Feng Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Zettl%2C+A">Alex Zettl</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2006.04000v1-abstract-short" style="display: inline;"> Two-dimensional heterostructures with layers of slightly different lattice vectors exhibit a new periodic structure known as moire lattices. Moire lattice formation provides a powerful new way to engineer the electronic structure of two-dimensional materials for realizing novel correlated and topological phenomena. In addition, superstructures of moire lattices can emerge from multiple misaligned… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2006.04000v1-abstract-full').style.display = 'inline'; document.getElementById('2006.04000v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2006.04000v1-abstract-full" style="display: none;"> Two-dimensional heterostructures with layers of slightly different lattice vectors exhibit a new periodic structure known as moire lattices. Moire lattice formation provides a powerful new way to engineer the electronic structure of two-dimensional materials for realizing novel correlated and topological phenomena. In addition, superstructures of moire lattices can emerge from multiple misaligned lattice vectors or inhomogeneous strain distribution, which offers an extra degree of freedom in the electronic band structure design. High-resolution imaging of the moire lattices and superstructures is critical for quantitative understanding of emerging moire physics. Here we report the nanoscale imaging of moire lattices and superstructures in various graphene-based samples under ambient conditions using an ultra-high-resolution implementation of scanning microwave impedance microscopy. We show that, quite remarkably, although the scanning probe tip has a gross radius of ~100 nm, an ultra-high spatial resolution in local conductivity profiles better than 5 nm can be achieved. This resolution enhancement not only enables to directly visualize the moire lattices in magic-angle twisted double bilayer graphene and composite super-moire lattices, but also allows design path toward artificial synthesis of novel moire superstructures such as the Kagome moire from the interplay and the supermodulation between twisted graphene and hexagonal boron nitride layers. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2006.04000v1-abstract-full').style.display = 'none'; document.getElementById('2006.04000v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 6 June, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">16 pages, 5 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Science Advances 2020, 6, eabd1919 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1904.11010">arXiv:1904.11010</a> <span> [<a href="https://arxiv.org/pdf/1904.11010">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41567-019-0744-9">10.1038/s41567-019-0744-9 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Visualizing Exotic Orbital Texture in the Single-Layer Mott Insulator 1T-TaSe2 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Chen%2C+Y">Yi Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Ruan%2C+W">Wei Ruan</a>, <a href="/search/cond-mat?searchtype=author&query=Wu%2C+M">Meng Wu</a>, <a href="/search/cond-mat?searchtype=author&query=Tang%2C+S">Shujie Tang</a>, <a href="/search/cond-mat?searchtype=author&query=Ryu%2C+H">Hyejin Ryu</a>, <a href="/search/cond-mat?searchtype=author&query=Tsai%2C+H">Hsin-Zon Tsai</a>, <a href="/search/cond-mat?searchtype=author&query=Lee%2C+R">Ryan Lee</a>, <a href="/search/cond-mat?searchtype=author&query=Kahn%2C+S">Salman Kahn</a>, <a href="/search/cond-mat?searchtype=author&query=Liou%2C+F">Franklin Liou</a>, <a href="/search/cond-mat?searchtype=author&query=Jia%2C+C">Caihong Jia</a>, <a href="/search/cond-mat?searchtype=author&query=Albertini%2C+O+R">Oliver R. Albertini</a>, <a href="/search/cond-mat?searchtype=author&query=Xiong%2C+H">Hongyu Xiong</a>, <a href="/search/cond-mat?searchtype=author&query=Jia%2C+T">Tao Jia</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+Z">Zhi Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Sobota%2C+J+A">Jonathan A. Sobota</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+A+Y">Amy Y. Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Moore%2C+J+E">Joel E. Moore</a>, <a href="/search/cond-mat?searchtype=author&query=Shen%2C+Z">Zhi-Xun Shen</a>, <a href="/search/cond-mat?searchtype=author&query=Louie%2C+S+G">Steven G. Louie</a>, <a href="/search/cond-mat?searchtype=author&query=Mo%2C+S">Sung-Kwan Mo</a>, <a href="/search/cond-mat?searchtype=author&query=Crommie%2C+M+F">Michael F. Crommie</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1904.11010v2-abstract-short" style="display: inline;"> Mott insulating behavior is induced by strong electron correlation and can lead to exotic states of matter such as unconventional superconductivity and quantum spin liquids. Recent advances in van der Waals material synthesis enable the exploration of novel Mott systems in the two-dimensional limit. Here we report characterization of the local electronic properties of single- and few-layer 1T-TaSe… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1904.11010v2-abstract-full').style.display = 'inline'; document.getElementById('1904.11010v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1904.11010v2-abstract-full" style="display: none;"> Mott insulating behavior is induced by strong electron correlation and can lead to exotic states of matter such as unconventional superconductivity and quantum spin liquids. Recent advances in van der Waals material synthesis enable the exploration of novel Mott systems in the two-dimensional limit. Here we report characterization of the local electronic properties of single- and few-layer 1T-TaSe2 via spatial- and momentum-resolved spectroscopy involving scanning tunneling microscopy and angle-resolved photoemission. Our combined experimental and theoretical study indicates that electron correlation induces a robust Mott insulator state in single-layer 1T-TaSe2 that is accompanied by novel orbital texture. Inclusion of interlayer coupling weakens the insulating phase in 1T-TaSe2, as seen by strong reduction of its energy gap and quenching of its correlation-driven orbital texture in bilayer and trilayer 1T-TaSe2. Our results establish single-layer 1T-TaSe2 as a useful new platform for investigating strong correlation physics in two dimensions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1904.11010v2-abstract-full').style.display = 'none'; document.getElementById('1904.11010v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 May, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 24 April, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Physics 16, 218-224 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1809.05209">arXiv:1809.05209</a> <span> [<a href="https://arxiv.org/pdf/1809.05209">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1021/acs.nanolett.8b01972">10.1021/acs.nanolett.8b01972 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Visualization and Control of Single Electron Charging in Bilayer Graphene Quantum Dots </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Velasco%2C+J">Jairo Velasco Jr.</a>, <a href="/search/cond-mat?searchtype=author&query=Lee%2C+J">Juwon Lee</a>, <a href="/search/cond-mat?searchtype=author&query=Wong%2C+D">Dillon Wong</a>, <a href="/search/cond-mat?searchtype=author&query=Kahn%2C+S">Salman Kahn</a>, <a href="/search/cond-mat?searchtype=author&query=Tsai%2C+H">Hsin-Zon Tsai</a>, <a href="/search/cond-mat?searchtype=author&query=Costello%2C+J">Joseph Costello</a>, <a href="/search/cond-mat?searchtype=author&query=Umeda%2C+T">Torben Umeda</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Zettl%2C+A">Alex Zettl</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+F">Feng Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Crommie%2C+M+F">Michael F. Crommie</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1809.05209v1-abstract-short" style="display: inline;"> Graphene p-n junctions provide an ideal platform for investigating novel behavior at the boundary between electronics and optics that arise from massless Dirac fermions, such as whispering gallery modes and Veselago lensing. Bilayer graphene also hosts Dirac fermions, but they differ from single-layer graphene charge carriers because they are massive, can be gapped by an applied perpendicular elec… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1809.05209v1-abstract-full').style.display = 'inline'; document.getElementById('1809.05209v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1809.05209v1-abstract-full" style="display: none;"> Graphene p-n junctions provide an ideal platform for investigating novel behavior at the boundary between electronics and optics that arise from massless Dirac fermions, such as whispering gallery modes and Veselago lensing. Bilayer graphene also hosts Dirac fermions, but they differ from single-layer graphene charge carriers because they are massive, can be gapped by an applied perpendicular electric field, and have very different pseudospin selection rules across a p-n junction. Novel phenomena predicted for these massive Dirac fermions at p-n junctions include anti-Klein tunneling, oscillatory Zener tunneling, and electron cloaked states. Despite these predictions there has been little experimental focus on the microscopic spatial behavior of massive Dirac fermions in the presence of p-n junctions. Here we report the experimental manipulation and characterization of massive Dirac fermions within bilayer graphene quantum dots defined by circular p-n junctions through the use of scanning tunneling microscopy-based (STM) methods. Our p-n junctions are created via a flexible technique that enables realization of exposed quantum dots in bilayer graphene/hBN heterostructures. These quantum dots exhibit sharp spectroscopic resonances that disperse in energy as a function of applied gate voltage. Spatial maps of these features show prominent concentric rings with diameters that can be tuned by an electrostatic gate. This behavior is explained by single-electron charging of localized states that arise from the quantum confinement of massive Dirac fermions within our exposed bilayer graphene quantum dots. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1809.05209v1-abstract-full').style.display = 'none'; document.getElementById('1809.05209v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 September, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nano Lett., 2018, 18 (8), 5104 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1712.00820">arXiv:1712.00820</a> <span> [<a href="https://arxiv.org/pdf/1712.00820">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Strongly Correlated Electrons">cond-mat.str-el</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevLett.119.087401">10.1103/PhysRevLett.119.087401 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Optically discriminating carrier-induced quasiparticle band gap and exciton energy renormalization in monolayer MoS2 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Yao%2C+K">Kaiyuan Yao</a>, <a href="/search/cond-mat?searchtype=author&query=Yan%2C+A">Aiming Yan</a>, <a href="/search/cond-mat?searchtype=author&query=Kahn%2C+S">Salman Kahn</a>, <a href="/search/cond-mat?searchtype=author&query=Suslu%2C+A">Aslihan Suslu</a>, <a href="/search/cond-mat?searchtype=author&query=Liang%2C+Y">Yufeng Liang</a>, <a href="/search/cond-mat?searchtype=author&query=Barnard%2C+E+S">Edward S. Barnard</a>, <a href="/search/cond-mat?searchtype=author&query=Tongay%2C+S">Sefaattin Tongay</a>, <a href="/search/cond-mat?searchtype=author&query=Zettl%2C+A">Alex Zettl</a>, <a href="/search/cond-mat?searchtype=author&query=Borys%2C+N+J">Nicholas J. Borys</a>, <a href="/search/cond-mat?searchtype=author&query=Schuck%2C+P+J">P. James Schuck</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1712.00820v1-abstract-short" style="display: inline;"> Optoelectronic excitations in monolayer MoS2 manifest from a hierarchy of electrically tunable, Coulombic free-carrier and excitonic many-body phenomena. Investigating the fundamental interactions underpinning these phenomena - critical to both many-body physics exploration and device applications - presents challenges, however, due to a complex balance of competing optoelectronic effects and inte… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1712.00820v1-abstract-full').style.display = 'inline'; document.getElementById('1712.00820v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1712.00820v1-abstract-full" style="display: none;"> Optoelectronic excitations in monolayer MoS2 manifest from a hierarchy of electrically tunable, Coulombic free-carrier and excitonic many-body phenomena. Investigating the fundamental interactions underpinning these phenomena - critical to both many-body physics exploration and device applications - presents challenges, however, due to a complex balance of competing optoelectronic effects and interdependent properties. Here, optical detection of bound- and free-carrier photoexcitations is used to directly quantify carrier-induced changes of the quasiparticle band gap and exciton binding energies. The results explicitly disentangle the competing effects and highlight longstanding theoretical predictions of large carrier-induced band gap and exciton renormalization in 2D semiconductors. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1712.00820v1-abstract-full').style.display = 'none'; document.getElementById('1712.00820v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 3 December, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 119, 087401 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1703.03151">arXiv:1703.03151</a> <span> [<a href="https://arxiv.org/pdf/1703.03151">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/nphys4174">10.1038/nphys4174 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Realization of Quantum Spin Hall State in Monolayer 1T'-WTe2 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Tang%2C+S">Shujie Tang</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+C">Chaofan Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Wong%2C+D">Dillon Wong</a>, <a href="/search/cond-mat?searchtype=author&query=Pedramrazi%2C+Z">Zahra Pedramrazi</a>, <a href="/search/cond-mat?searchtype=author&query=Tsai%2C+H">Hsin-Zon Tsai</a>, <a href="/search/cond-mat?searchtype=author&query=Jia%2C+C">Chunjing Jia</a>, <a href="/search/cond-mat?searchtype=author&query=Moritz%2C+B">Brian Moritz</a>, <a href="/search/cond-mat?searchtype=author&query=Claassen%2C+M">Martin Claassen</a>, <a href="/search/cond-mat?searchtype=author&query=Ryu%2C+H">Hyejin Ryu</a>, <a href="/search/cond-mat?searchtype=author&query=Kahn%2C+S">Salman Kahn</a>, <a href="/search/cond-mat?searchtype=author&query=Jiang%2C+J">Juan Jiang</a>, <a href="/search/cond-mat?searchtype=author&query=Yan%2C+H">Hao Yan</a>, <a href="/search/cond-mat?searchtype=author&query=Hashimoto%2C+M">Makoto Hashimoto</a>, <a href="/search/cond-mat?searchtype=author&query=Lu%2C+D">Donghui Lu</a>, <a href="/search/cond-mat?searchtype=author&query=Moore%2C+R+G">Robert G. Moore</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+C">Chancuk Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Hwang%2C+C">Choongyu Hwang</a>, <a href="/search/cond-mat?searchtype=author&query=Hussain%2C+Z">Zahid Hussain</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+Y">Yulin Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Ugeda%2C+M+M">Miguel M. Ugeda</a>, <a href="/search/cond-mat?searchtype=author&query=Liu%2C+Z">Zhi Liu</a>, <a href="/search/cond-mat?searchtype=author&query=Xie%2C+X">Xiaoming Xie</a>, <a href="/search/cond-mat?searchtype=author&query=Devereaux%2C+T+P">Thomas P. Devereaux</a>, <a href="/search/cond-mat?searchtype=author&query=Crommie%2C+M+F">Michael F. Crommie</a>, <a href="/search/cond-mat?searchtype=author&query=Mo%2C+S">Sung-Kwan Mo</a> , et al. (1 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1703.03151v1-abstract-short" style="display: inline;"> A quantum spin Hall (QSH) insulator is a novel two-dimensional quantum state of matter that features quantized Hall conductance in the absence of magnetic field, resulting from topologically protected dissipationless edge states that bridge the energy gap opened by band inversion and strong spin-orbit coupling. By investigating electronic structure of epitaxially grown monolayer 1T'-WTe2 using ang… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1703.03151v1-abstract-full').style.display = 'inline'; document.getElementById('1703.03151v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1703.03151v1-abstract-full" style="display: none;"> A quantum spin Hall (QSH) insulator is a novel two-dimensional quantum state of matter that features quantized Hall conductance in the absence of magnetic field, resulting from topologically protected dissipationless edge states that bridge the energy gap opened by band inversion and strong spin-orbit coupling. By investigating electronic structure of epitaxially grown monolayer 1T'-WTe2 using angle-resolved photoemission (ARPES) and first principle calculations, we observe clear signatures of the topological band inversion and the band gap opening, which are the hallmarks of a QSH state. Scanning tunneling microscopy measurements further confirm the correct crystal structure and the existence of a bulk band gap, and provide evidence for a modified electronic structure near the edge that is consistent with the expectations for a QSH insulator. Our results establish monolayer 1T'-WTe2 as a new class of QSH insulator with large band gap in a robust two-dimensional materials family of transition metal dichalcogenides (TMDCs). <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1703.03151v1-abstract-full').style.display = 'none'; document.getElementById('1703.03151v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 March, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">19 pages, 4 figures; includes Supplemental Material (11 pages, 7 figures)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1612.05359">arXiv:1612.05359</a> <span> [<a href="https://arxiv.org/pdf/1612.05359">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> </div> <p class="title is-5 mathjax"> Observation of Ultralong Valley Lifetime in WSe2/MoS2 Heterostructures </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Kim%2C+J">Jonghwan Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Jin%2C+C">Chenhao Jin</a>, <a href="/search/cond-mat?searchtype=author&query=Chen%2C+B">Bin Chen</a>, <a href="/search/cond-mat?searchtype=author&query=Cai%2C+H">Hui Cai</a>, <a href="/search/cond-mat?searchtype=author&query=Zhao%2C+T">Tao Zhao</a>, <a href="/search/cond-mat?searchtype=author&query=Lee%2C+P">Puiyee Lee</a>, <a href="/search/cond-mat?searchtype=author&query=Kahn%2C+S">Salman Kahn</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Tongay%2C+S">Sefaattin Tongay</a>, <a href="/search/cond-mat?searchtype=author&query=Crommie%2C+M+F">Michael F. Crommie</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+F">Feng Wang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1612.05359v1-abstract-short" style="display: inline;"> The valley degree of freedom in two-dimensional (2D) crystals recently emerged as a novel information carrier in addition to spin and charge. The intrinsic valley lifetime in 2D transition metal dichalcoginides (TMD) is expected to be remarkably long due to the unique spin-valley locking behavior, where the inter-valley scattering of electron requires simultaneously a large momentum transfer to th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1612.05359v1-abstract-full').style.display = 'inline'; document.getElementById('1612.05359v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1612.05359v1-abstract-full" style="display: none;"> The valley degree of freedom in two-dimensional (2D) crystals recently emerged as a novel information carrier in addition to spin and charge. The intrinsic valley lifetime in 2D transition metal dichalcoginides (TMD) is expected to be remarkably long due to the unique spin-valley locking behavior, where the inter-valley scattering of electron requires simultaneously a large momentum transfer to the opposite valley and a flip of the electron spin. The experimentally observed valley lifetime in 2D TMDs, however, has been limited to tens of nanoseconds so far. Here we report efficient generation of microsecond-long lived valley polarization in WSe2/MoS2 heterostructures by exploiting the ultrafast charge transfer processes in the heterostructure that efficiently creates resident holes in the WSe2 layer. These valley-polarized holes exhibit near unity valley polarization and ultralong valley lifetime: we observe a valley-polarized hole population lifetime of over 1 us, and a valley depolarization lifetime (i.e. inter-valley scattering lifetime) over 40 us at 10 Kelvin. The near-perfect generation of valley-polarized holes in TMD heterostructures with ultralong valley lifetime, orders of magnitude longer than previous results, opens up new opportunities for novel valleytronics and spintronics applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1612.05359v1-abstract-full').style.display = 'none'; document.getElementById('1612.05359v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 December, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">21 pages, 6 figures, Jonghwan Kim and Chenhao Jin contributed equally to this work</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1606.03654">arXiv:1606.03654</a> <span> [<a href="https://arxiv.org/pdf/1606.03654">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/nphys3805">10.1038/nphys3805 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Imaging electrostatically confined Dirac fermions in graphene quantum dots </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Lee%2C+J">Juwon Lee</a>, <a href="/search/cond-mat?searchtype=author&query=Wong%2C+D">Dillon Wong</a>, <a href="/search/cond-mat?searchtype=author&query=Velasco%2C+J">Jairo Velasco Jr.</a>, <a href="/search/cond-mat?searchtype=author&query=Rodriguez-Nieva%2C+J+F">Joaquin F. Rodriguez-Nieva</a>, <a href="/search/cond-mat?searchtype=author&query=Kahn%2C+S">Salman Kahn</a>, <a href="/search/cond-mat?searchtype=author&query=Tsai%2C+H">Hsin-Zon Tsai</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Zettl%2C+A">Alex Zettl</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+F">Feng Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Levitov%2C+L+S">Leonid S. Levitov</a>, <a href="/search/cond-mat?searchtype=author&query=Crommie%2C+M+F">Michael F. Crommie</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1606.03654v1-abstract-short" style="display: inline;"> Electrostatic confinement of charge carriers in graphene is governed by Klein tunneling, a relativistic quantum process in which particle-hole transmutation leads to unusual anisotropic transmission at pn junction boundaries. Reflection and transmission at these novel potential barriers should affect the quantum interference of electronic wavefunctions near these boundaries. Here we report the use… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1606.03654v1-abstract-full').style.display = 'inline'; document.getElementById('1606.03654v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1606.03654v1-abstract-full" style="display: none;"> Electrostatic confinement of charge carriers in graphene is governed by Klein tunneling, a relativistic quantum process in which particle-hole transmutation leads to unusual anisotropic transmission at pn junction boundaries. Reflection and transmission at these novel potential barriers should affect the quantum interference of electronic wavefunctions near these boundaries. Here we report the use of scanning tunneling microscopy (STM) to map the electronic structure of Dirac fermions confined by circular graphene pn junctions. These effective quantum dots were fabricated using a new technique involving local manipulation of defect charge within the insulating substrate beneath a graphene monolayer. Inside such graphene quantum dots we observe energy levels corresponding to quasi-bound states and we spatially visualize the quantum interference patterns of confined electrons. Dirac fermions outside these quantum dots exhibit Friedel oscillation-like behavior. Bolstered with a theoretical model describing relativistic particles in a harmonic oscillator potential, our findings yield new insight into the spatial behavior of electrostatically confined Dirac fermions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1606.03654v1-abstract-full').style.display = 'none'; document.getElementById('1606.03654v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 June, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">4 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1602.03245">arXiv:1602.03245</a> <span> [<a href="https://arxiv.org/pdf/1602.03245">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1021/acs.nanolett.5b04441">10.1021/acs.nanolett.5b04441 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Nanoscale control of rewriteable doping patterns in pristine graphene/boron nitride heterostructures </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Velasco%2C+J">Jairo Velasco Jr.</a>, <a href="/search/cond-mat?searchtype=author&query=Ju%2C+L">Long Ju</a>, <a href="/search/cond-mat?searchtype=author&query=Wong%2C+D">Dillon Wong</a>, <a href="/search/cond-mat?searchtype=author&query=Kahn%2C+S">Salman Kahn</a>, <a href="/search/cond-mat?searchtype=author&query=Lee%2C+J">Juwon Lee</a>, <a href="/search/cond-mat?searchtype=author&query=Tsai%2C+H">Hsin-Zon Tsai</a>, <a href="/search/cond-mat?searchtype=author&query=Germany%2C+C">Chad Germany</a>, <a href="/search/cond-mat?searchtype=author&query=Wickenburg%2C+S">Sebastian Wickenburg</a>, <a href="/search/cond-mat?searchtype=author&query=Lu%2C+J">Jiong Lu</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Zettl%2C+A">Alex Zettl</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+F">Feng Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Crommie%2C+M+F">Michael F. Crommie</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1602.03245v1-abstract-short" style="display: inline;"> Nanoscale control of charge doping in two-dimensional (2D) materials permits the realization of electronic analogs of optical phenomena, relativistic physics at low energies, and technologically promising nanoelectronics. Electrostatic gating and chemical doping are the two most common methods to achieve local control of such doping. However, these approaches suffer from complicated fabrication pr… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.03245v1-abstract-full').style.display = 'inline'; document.getElementById('1602.03245v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1602.03245v1-abstract-full" style="display: none;"> Nanoscale control of charge doping in two-dimensional (2D) materials permits the realization of electronic analogs of optical phenomena, relativistic physics at low energies, and technologically promising nanoelectronics. Electrostatic gating and chemical doping are the two most common methods to achieve local control of such doping. However, these approaches suffer from complicated fabrication processes that introduce contamination, change material properties irreversibly, and lack flexible pattern control. Here we demonstrate a clean, simple, and reversible technique that permits writing, reading, and erasing of doping patterns for 2D materials at the nanometer scale. We accomplish this by employing a graphene/boron nitride (BN) heterostructure that is equipped with a bottom gate electrode. By using electron transport and scanning tunneling microscopy (STM), we demonstrate that spatial control of charge doping can be realized with the application of either light or STM tip voltage excitations in conjunction with a gate electric field. Our straightforward and novel technique provides a new path towards on-demand graphene pn junctions and ultra-thin memory devices. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.03245v1-abstract-full').style.display = 'none'; document.getElementById('1602.03245v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 February, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted at Nano Letters</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1510.02888">arXiv:1510.02888</a> <span> [<a href="https://arxiv.org/pdf/1510.02888">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevB.92.155409">10.1103/PhysRevB.92.155409 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Local spectroscopy of moir茅-induced electronic structure in gate-tunable twisted bilayer graphene </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Wong%2C+D">Dillon Wong</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+Y">Yang Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Jung%2C+J">Jeil Jung</a>, <a href="/search/cond-mat?searchtype=author&query=Pezzini%2C+S">Sergio Pezzini</a>, <a href="/search/cond-mat?searchtype=author&query=DaSilva%2C+A+M">Ashley M. DaSilva</a>, <a href="/search/cond-mat?searchtype=author&query=Tsai%2C+H">Hsin-Zon Tsai</a>, <a href="/search/cond-mat?searchtype=author&query=Jung%2C+H+S">Han Sae Jung</a>, <a href="/search/cond-mat?searchtype=author&query=Khajeh%2C+R">Ramin Khajeh</a>, <a href="/search/cond-mat?searchtype=author&query=Kim%2C+Y">Youngkyou Kim</a>, <a href="/search/cond-mat?searchtype=author&query=Lee%2C+J">Juwon Lee</a>, <a href="/search/cond-mat?searchtype=author&query=Kahn%2C+S">Salman Kahn</a>, <a href="/search/cond-mat?searchtype=author&query=Tollabimazraehno%2C+S">Sajjad Tollabimazraehno</a>, <a href="/search/cond-mat?searchtype=author&query=Rasool%2C+H">Haider Rasool</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Zettl%2C+A">Alex Zettl</a>, <a href="/search/cond-mat?searchtype=author&query=Adam%2C+S">Shaffique Adam</a>, <a href="/search/cond-mat?searchtype=author&query=MacDonald%2C+A+H">Allan H. MacDonald</a>, <a href="/search/cond-mat?searchtype=author&query=Crommie%2C+M+F">Michael F. Crommie</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1510.02888v1-abstract-short" style="display: inline;"> Twisted bilayer graphene (tBLG) forms a quasicrystal whose structural and electronic properties depend on the angle of rotation between its layers. Here we present a scanning tunneling microscopy study of gate-tunable tBLG devices supported by atomically-smooth and chemically inert hexagonal boron nitride (BN). The high quality of these tBLG devices allows identification of coexisting moir茅 patter… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1510.02888v1-abstract-full').style.display = 'inline'; document.getElementById('1510.02888v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1510.02888v1-abstract-full" style="display: none;"> Twisted bilayer graphene (tBLG) forms a quasicrystal whose structural and electronic properties depend on the angle of rotation between its layers. Here we present a scanning tunneling microscopy study of gate-tunable tBLG devices supported by atomically-smooth and chemically inert hexagonal boron nitride (BN). The high quality of these tBLG devices allows identification of coexisting moir茅 patterns and moir茅 super-superlattices produced by graphene-graphene and graphene-BN interlayer interactions. Furthermore, we examine additional tBLG spectroscopic features in the local density of states beyond the first van Hove singularity. Our experimental data is explained by a theory of moir茅 bands that incorporates ab initio calculations and confirms the strongly non-perturbative character of tBLG interlayer coupling in the small twist-angle regime. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1510.02888v1-abstract-full').style.display = 'none'; document.getElementById('1510.02888v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 October, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. B 92, 155409 (2015) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1504.06641">arXiv:1504.06641</a> <span> [<a href="https://arxiv.org/pdf/1504.06641">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1021/acs.nanolett.5b01311">10.1021/acs.nanolett.5b01311 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Direct growth of single- and few-layer MoS2 on h-BN with preferred relative rotation angles </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Yan%2C+A">Aiming Yan</a>, <a href="/search/cond-mat?searchtype=author&query=Velasco%2C%2C+J">Jairo Velasco, Jr.</a>, <a href="/search/cond-mat?searchtype=author&query=Kahn%2C+S">Salman Kahn</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+F">Feng Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Crommie%2C+M+F">Michael F. Crommie</a>, <a href="/search/cond-mat?searchtype=author&query=Zettl%2C+A">Alex Zettl</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1504.06641v3-abstract-short" style="display: inline;"> Monolayer molybdenum disulphide (MoS2) is a promising two-dimensional direct-bandgap semiconductor with potential applications in atomically thin and flexible electronics. An attractive insulating substrate or mate for MoS2 (and related materials such as graphene) is hexagonal boron nitride (h-BN). Stacked heterostructures of MoS2 and h-BN have been produced by manual transfer methods, but a more… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1504.06641v3-abstract-full').style.display = 'inline'; document.getElementById('1504.06641v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1504.06641v3-abstract-full" style="display: none;"> Monolayer molybdenum disulphide (MoS2) is a promising two-dimensional direct-bandgap semiconductor with potential applications in atomically thin and flexible electronics. An attractive insulating substrate or mate for MoS2 (and related materials such as graphene) is hexagonal boron nitride (h-BN). Stacked heterostructures of MoS2 and h-BN have been produced by manual transfer methods, but a more efficient and scalable assembly method is needed. Here we demonstrate the direct growth of single- and few-layer MoS2 on h-BN by chemical vapor deposition (CVD) method, which is scalable with suitably structured substrates. The growth mechanisms for single-layer and few-layer samples are found to be distinct, and for single-layer samples low relative rotation angles (<5 degree) between the MoS2 and h-BN lattices prevail. Moreover, MoS2 directly grown on h-BN maintains its intrinsic 1.89 eV bandgap. Our CVD synthesis method presents an important advancement towards controllable and scalable MoS2 based electronic devices. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1504.06641v3-abstract-full').style.display = 'none'; document.getElementById('1504.06641v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 31 August, 2015; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 24 April, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">22 pages, 5 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1412.1878">arXiv:1412.1878</a> <span> [<a href="https://arxiv.org/pdf/1412.1878">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> </div> <p class="title is-5 mathjax"> Characterization and manipulation of individual defects in insulating hexagonal boron nitride using scanning tunneling microscopy </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Wong%2C+D">Dillon Wong</a>, <a href="/search/cond-mat?searchtype=author&query=Velasco%2C+J">Jairo Velasco Jr.</a>, <a href="/search/cond-mat?searchtype=author&query=Ju%2C+L">Long Ju</a>, <a href="/search/cond-mat?searchtype=author&query=Lee%2C+J">Juwon Lee</a>, <a href="/search/cond-mat?searchtype=author&query=Kahn%2C+S">Salman Kahn</a>, <a href="/search/cond-mat?searchtype=author&query=Tsai%2C+H">Hsin-Zon Tsai</a>, <a href="/search/cond-mat?searchtype=author&query=Germany%2C+C">Chad Germany</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">Takashi Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">Kenji Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Zettl%2C+A">Alex Zettl</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+F">Feng Wang</a>, <a href="/search/cond-mat?searchtype=author&query=Crommie%2C+M+F">Michael F. Crommie</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1412.1878v1-abstract-short" style="display: inline;"> Defects play a key role in determining the properties of most materials and, because they tend to be highly localized, characterizing them at the single-defect level is particularly important. Scanning tunneling microscopy (STM) has a history of imaging the electronic structure of individual point defects in conductors, semiconductors, and ultrathin films, but single-defect electronic characteriza… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1412.1878v1-abstract-full').style.display = 'inline'; document.getElementById('1412.1878v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1412.1878v1-abstract-full" style="display: none;"> Defects play a key role in determining the properties of most materials and, because they tend to be highly localized, characterizing them at the single-defect level is particularly important. Scanning tunneling microscopy (STM) has a history of imaging the electronic structure of individual point defects in conductors, semiconductors, and ultrathin films, but single-defect electronic characterization at the nanometer-scale remains an elusive goal for intrinsic bulk insulators. Here we report the characterization and manipulation of individual native defects in an intrinsic bulk hexagonal boron nitride (BN) insulator via STM. Normally, this would be impossible due to the lack of a conducting drain path for electrical current. We overcome this problem by employing a graphene/BN heterostructure, which exploits graphene's atomically thin nature to allow visualization of defect phenomena in the underlying bulk BN. We observe three different defect structures that we attribute to defects within the bulk insulating boron nitride. Using scanning tunneling spectroscopy (STS), we obtain charge and energy-level information for these BN defect structures. In addition to characterizing such defects, we find that it is also possible to manipulate them through voltage pulses applied to our STM tip. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1412.1878v1-abstract-full').style.display = 'none'; document.getElementById('1412.1878v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 December, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">16 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Nanotechnology 10 949 (2015) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1402.4563">arXiv:1402.4563</a> <span> [<a href="https://arxiv.org/pdf/1402.4563">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Mesoscale and Nanoscale Physics">cond-mat.mes-hall</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Materials Science">cond-mat.mtrl-sci</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/nnano.2014.60">10.1038/nnano.2014.60 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Photo-induced Doping in Graphene/Boron Nitride Heterostructures </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Ju%2C+L">L. Ju</a>, <a href="/search/cond-mat?searchtype=author&query=Velasco%2C+J">J. Velasco Jr.</a>, <a href="/search/cond-mat?searchtype=author&query=Huang%2C+E">E. Huang</a>, <a href="/search/cond-mat?searchtype=author&query=Kahn%2C+S">S. Kahn</a>, <a href="/search/cond-mat?searchtype=author&query=Nosiglia%2C+C">C. Nosiglia</a>, <a href="/search/cond-mat?searchtype=author&query=Tsai%2C+H">H. Tsai</a>, <a href="/search/cond-mat?searchtype=author&query=Yang%2C+W">W. Yang</a>, <a href="/search/cond-mat?searchtype=author&query=Taniguchi%2C+T">T. Taniguchi</a>, <a href="/search/cond-mat?searchtype=author&query=Watanabe%2C+K">K. Watanabe</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+Y">Y. Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Zhang%2C+G">G. Zhang</a>, <a href="/search/cond-mat?searchtype=author&query=Crommie%2C+M">M. Crommie</a>, <a href="/search/cond-mat?searchtype=author&query=Zettl%2C+A">A. Zettl</a>, <a href="/search/cond-mat?searchtype=author&query=Wang%2C+F">F. Wang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1402.4563v1-abstract-short" style="display: inline;"> The design of stacks of layered materials in which adjacent layers interact by van der Waals forces[1] has enabled the combination of various two-dimensional crystals with different electrical, optical and mechanical properties, and the emergence of novel physical phenomena and device functionality[2-8]. Here we report photo-induced doping in van der Waals heterostructures (VDHs) consisting of gra… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1402.4563v1-abstract-full').style.display = 'inline'; document.getElementById('1402.4563v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1402.4563v1-abstract-full" style="display: none;"> The design of stacks of layered materials in which adjacent layers interact by van der Waals forces[1] has enabled the combination of various two-dimensional crystals with different electrical, optical and mechanical properties, and the emergence of novel physical phenomena and device functionality[2-8]. Here we report photo-induced doping in van der Waals heterostructures (VDHs) consisting of graphene and boron nitride layers. It enables flexible and repeatable writing and erasing of charge doping in graphene with visible light. We demonstrate that this photo-induced doping maintains the high carrier mobility of the graphene-boron nitride (G/BN) heterostructure, which resembles the modulation doping technique used in semiconductor heterojunctions, and can be used to generate spatially-varying doping profiles such as p-n junctions. We show that this photo-induced doping arises from microscopically coupled optical and electrical responses of G/BN heterostructures, which includes optical excitation of defect transitions in boron nitride, electrical transport in graphene, and charge transfer between boron nitride and graphene. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1402.4563v1-abstract-full').style.display = 'none'; document.getElementById('1402.4563v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 February, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nature Nanotechnology 9 348 (2014) </p> </li> </ol> <div class="is-hidden-tablet">  <span class="help" style="display: inline-block;"><a href="https://github.com/arXiv/arxiv-search/releases">Search v0.5.6 released 2020-02-24</a>  </span> </div> </div> </main> <footer> <div class="columns is-desktop" role="navigation" aria-label="Secondary">  <div class="column"> <div class="columns"> <div class="column"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/about">About</a></li> <li><a href="https://info.arxiv.org/help">Help</a></li> </ul> </div> <div class="column"> <ul class="nav-spaced"> <li> <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><title>contact arXiv</title><desc>Click here to contact arXiv</desc><path d="M502.3 190.8c3.9-3.1 9.7-.2 9.7 4.7V400c0 26.5-21.5 48-48 48H48c-26.5 0-48-21.5-48-48V195.6c0-5 5.7-7.8 9.7-4.7 22.4 17.4 52.1 39.5 154.1 113.6 21.1 15.4 56.7 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