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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/2210.02691">arXiv:2210.02691</a> <span> [<a href="https://arxiv.org/pdf/2210.02691">pdf</a>, <a href="https://arxiv.org/ps/2210.02691">ps</a>, <a href="https://arxiv.org/format/2210.02691">other</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/10.1103/PhysRevB.107.134106">10.1103/PhysRevB.107.134106 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Kinetically Decoupled Electrical and Structural Phase Transitions in VO2 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Sahu%2C+S+R">S. R. Sahu</a>, <a href="/search/cond-mat?searchtype=author&query=Majid%2C+S+S">S. S. Majid</a>, <a href="/search/cond-mat?searchtype=author&query=Ahad%2C+A">A. Ahad</a>, <a href="/search/cond-mat?searchtype=author&query=Tripathy%2C+A">A. Tripathy</a>, <a href="/search/cond-mat?searchtype=author&query=Dey%2C+K">K. Dey</a>, <a href="/search/cond-mat?searchtype=author&query=Pal%2C+S">S. Pal</a>, <a href="/search/cond-mat?searchtype=author&query=De%2C+B+K">B. K. De</a>, <a href="/search/cond-mat?searchtype=author&query=Hsieh%2C+W">Wen-Pin Hsieh</a>, <a href="/search/cond-mat?searchtype=author&query=Rawat%2C+R">R. Rawat</a>, <a href="/search/cond-mat?searchtype=author&query=Sathe%2C+V+G">V. G. Sathe</a>, <a href="/search/cond-mat?searchtype=author&query=Shukla%2C+D+K">D. K. Shukla</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="2210.02691v1-abstract-short" style="display: inline;"> Vanadium dioxide (VO2) has drawn significant attention for its near room temperature insulator to metal transition and associated structural phase transition. The underlying Physics behind the temperature induced insulator to metal and concomitant structural phase transition in VO2 is yet to be fully understood. We have investigated the kinetics of the above phase transition behaviors of VO2 with… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.02691v1-abstract-full').style.display = 'inline'; document.getElementById('2210.02691v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2210.02691v1-abstract-full" style="display: none;"> Vanadium dioxide (VO2) has drawn significant attention for its near room temperature insulator to metal transition and associated structural phase transition. The underlying Physics behind the temperature induced insulator to metal and concomitant structural phase transition in VO2 is yet to be fully understood. We have investigated the kinetics of the above phase transition behaviors of VO2 with the help of resistivity measurements and Raman spectroscopy. Resistance thermal hysteresis scaling and relaxation measurements across the temperature induced insulator to metal transition reveal the unusual behaviour of this first-order phase transition, whereas Raman relaxation measurements show that the temperature induced structural phase transition in VO2 follows usual behaviour and is consistent with mean field prediction. At higher temperature sweeping rates decoupling of insulator to metal transition and structural phase transition have been confirmed. The observed anomalous first order phase transition behavior in VO2 is attributed to the unconventional quasi particle dynamics, i.e. significantly lowered electronic thermal conductivity across insulator to metal transition, which is confirmed by ultrafast optical pump-probe time domain thermoreflectance measurements. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.02691v1-abstract-full').style.display = 'none'; document.getElementById('2210.02691v1-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 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">25 pages, 8 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/2205.05972">arXiv:2205.05972</a> <span> [<a href="https://arxiv.org/pdf/2205.05972">pdf</a>, <a href="https://arxiv.org/ps/2205.05972">ps</a>, <a href="https://arxiv.org/format/2205.05972">other</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/10.1103/PhysRevB.103.L100205">10.1103/PhysRevB.103.L100205 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Coexistence of local structural heterogeneities and long-range ferroelectricity in Pb-free (1-x)Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 ceramics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Dey%2C+K">Koushik Dey</a>, <a href="/search/cond-mat?searchtype=author&query=Ahad%2C+A">Abdul Ahad</a>, <a href="/search/cond-mat?searchtype=author&query=Gautam%2C+K">Kamini Gautam</a>, <a href="/search/cond-mat?searchtype=author&query=Tripathy%2C+A">Abinash Tripathy</a>, <a href="/search/cond-mat?searchtype=author&query=Majid%2C+S+S">Sofi Suhail Majid</a>, <a href="/search/cond-mat?searchtype=author&query=Francoual%2C+S">Sonia Francoual</a>, <a href="/search/cond-mat?searchtype=author&query=Richter%2C+C">Carsten Richter</a>, <a href="/search/cond-mat?searchtype=author&query=Singh%2C+M">MN Singh</a>, <a href="/search/cond-mat?searchtype=author&query=Sagdeo%2C+A">Archna Sagdeo</a>, <a href="/search/cond-mat?searchtype=author&query=Welter%2C+E">Edmund Welter</a>, <a href="/search/cond-mat?searchtype=author&query=Vittayakorn%2C+N">Naratip Vittayakorn</a>, <a href="/search/cond-mat?searchtype=author&query=Sathe%2C+V+G">Vasant G. Sathe</a>, <a href="/search/cond-mat?searchtype=author&query=Rawat%2C+R">Rajeev Rawat</a>, <a href="/search/cond-mat?searchtype=author&query=Shukla%2C+D+K">Dinesh Kumar Shukla</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="2205.05972v1-abstract-short" style="display: inline;"> Environmentally benign (1-x)Ba(Ti$_{0.8}$Zr$_{0.2}$)O$_3$-x(Ba$_{0.7}$Ca$_{0.3}$)TiO$_3$ (BZT-BCT) ceramics are promising materials due to their remarkable high piezoresponse [Liu and Ren, Phys. Rev. Lett. \textbf{103}, 257602 (2009)]. In this Letter, by focusing on local and average structure in combination with macroscopic electromechanical and dielectric measurements we demonstrate the structur… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2205.05972v1-abstract-full').style.display = 'inline'; document.getElementById('2205.05972v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2205.05972v1-abstract-full" style="display: none;"> Environmentally benign (1-x)Ba(Ti$_{0.8}$Zr$_{0.2}$)O$_3$-x(Ba$_{0.7}$Ca$_{0.3}$)TiO$_3$ (BZT-BCT) ceramics are promising materials due to their remarkable high piezoresponse [Liu and Ren, Phys. Rev. Lett. \textbf{103}, 257602 (2009)]. In this Letter, by focusing on local and average structure in combination with macroscopic electromechanical and dielectric measurements we demonstrate the structure property relationship in the tetragonal BZT-BCT ceramic. During high-temperature cubic to tetragonal phase transformation, polar nanoregions are manifested through the spontaneous volume ferroelectrostriction at temperatures below $\sim$ 477 K. Temperature-dependent local structural investigations across the Zr K edge extended x-ray absorption fine structure spectroscopy reveal an anomalous collaboration between the ZrO$_{6}$ and TiO$_6$ octahedra. These octahedra compromise their individuality during polarization development. The presence of domains of submicron size embedded inside the macroscopic ferroelectric regions below T$_{m}$, as well as their hierarchical arrangement, is observed by piezo-response force microscopy. Effects of the existence of the structural/polar heterogeneities below T$_{m}$ are observed also when polarizibilities of the poled and the unpoled samples are compared; the poled sample is found to be more susceptible to the electric field. In addition, by using electric field dependent x-ray diffraction studies we also show that this ceramic under field exhibits reduction of tetragonal distortion, which is consistent with earlier reports. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2205.05972v1-abstract-full').style.display = 'none'; document.getElementById('2205.05972v1-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 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">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages, 6 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/2108.11977">arXiv:2108.11977</a> <span> [<a href="https://arxiv.org/pdf/2108.11977">pdf</a>, <a href="https://arxiv.org/format/2108.11977">other</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/10.1103/PhysRevB.105.024404">10.1103/PhysRevB.105.024404 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Pressure-induced collapse of ferromagnetism in Nickel </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Ahad%2C+A">A. Ahad</a>, <a href="/search/cond-mat?searchtype=author&query=Bahramy%2C+M+S">M. S. Bahramy</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="2108.11977v1-abstract-short" style="display: inline;"> Transition metals, Fe, Co and Ni, are the canonical systems for studying the effect of external perturbations on ferromagnetism. Among these, Ni stands out as it undergoes no structural phase transition under pressure. Here we have investigated the long-debated issue of pressure-induced magnetisation drop in Ni from first-principles. Our calculations confirm an abrupt quenching of magnetisation at… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2108.11977v1-abstract-full').style.display = 'inline'; document.getElementById('2108.11977v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2108.11977v1-abstract-full" style="display: none;"> Transition metals, Fe, Co and Ni, are the canonical systems for studying the effect of external perturbations on ferromagnetism. Among these, Ni stands out as it undergoes no structural phase transition under pressure. Here we have investigated the long-debated issue of pressure-induced magnetisation drop in Ni from first-principles. Our calculations confirm an abrupt quenching of magnetisation at high pressures, not associated with any structural phase transition. We find that the pressure substantially enhances the crystal field splitting of Ni-$3d$ orbitals, driving the system towards a new metallic phase violating the Stoner Criterion for ferromagnetic ordering. Analysing the charge populations in each spin channel, we show that the next nearest neighbour interactions play a crucial role in quenching ferromagnetic ordering in Ni and materials alike. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2108.11977v1-abstract-full').style.display = 'none'; document.getElementById('2108.11977v1-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> 26 August, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 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">5 pages, 5 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 105, 024404 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2004.08319">arXiv:2004.08319</a> <span> [<a href="https://arxiv.org/pdf/2004.08319">pdf</a>, <a href="https://arxiv.org/format/2004.08319">other</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="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/PhysRevB.102.094428">10.1103/PhysRevB.102.094428 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Magnetic correlations in subsystems of the misfit [Ca$_2$CoO$_3$]$_{0.62}$[CoO$_2$] cobaltate </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Ahad%2C+A">Abdul Ahad</a>, <a href="/search/cond-mat?searchtype=author&query=Gautam%2C+K">K. Gautam</a>, <a href="/search/cond-mat?searchtype=author&query=Dey%2C+K">K. Dey</a>, <a href="/search/cond-mat?searchtype=author&query=Majid%2C+S+S">S. S. Majid</a>, <a href="/search/cond-mat?searchtype=author&query=Rahman%2C+F">F. Rahman</a>, <a href="/search/cond-mat?searchtype=author&query=Sharma%2C+S+K">S. K. Sharma</a>, <a href="/search/cond-mat?searchtype=author&query=Coaquira%2C+J+A+H">J. A. H. Coaquira</a>, <a href="/search/cond-mat?searchtype=author&query=da+Silva%2C+I">Ivan da Silva</a>, <a href="/search/cond-mat?searchtype=author&query=Welter%2C+E">E. Welter</a>, <a href="/search/cond-mat?searchtype=author&query=Shukla%2C+D+K">D. K. Shukla</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="2004.08319v2-abstract-short" style="display: inline;"> [Ca$_2$CoO$_3$]$_{0.62}$[CoO$_2$], a two dimensional misfit metallic compound, is famous for its rich phases accessed by temperature, $i.e.$ high temperature spin-state transition, metal-insulator transition (MIT) at intermediate temperature ($\sim$ 100 K) and low temperature spin density wave (SDW). It enters into SDW phase below T$_{MIT}$ which becomes long range at 27 K. Information on the inde… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2004.08319v2-abstract-full').style.display = 'inline'; document.getElementById('2004.08319v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2004.08319v2-abstract-full" style="display: none;"> [Ca$_2$CoO$_3$]$_{0.62}$[CoO$_2$], a two dimensional misfit metallic compound, is famous for its rich phases accessed by temperature, $i.e.$ high temperature spin-state transition, metal-insulator transition (MIT) at intermediate temperature ($\sim$ 100 K) and low temperature spin density wave (SDW). It enters into SDW phase below T$_{MIT}$ which becomes long range at 27 K. Information on the independent role of misfit layers (rocksalt/Ca$_2$CoO$_3$ \& triangular/CoO$_2$) in these phases is scarce. By combining a set of complementary macroscopic (DC magnetization and resistivity) and microscopic (neutron diffraction and X-ray absorption fine structure spectroscopy) measurements on pure (CCO) and Tb substituted in the rocksalt layer of CCO (CCO1), magnetic correlations in both subsystems of this misfit compound are unraveled. CCO is found to exhibit glassiness, as well as exchange bias (EB) effects, while CCO1 does not exhibit glassiness, albeit it shows weaker EB effect. By combining local structure investigations from extended X-ray absorption fine structure (EXAFS) spectroscopy and neutron diffraction results on CCO, we confirm that the SDW arises in the CoO$_2$ layer. Our results show that the magnetocrystalline anisotropy associated with the rocksalt layer acts as a source of pinning, which is responsible for EB effect. Ferromagnetic clusters in the Ca$_2$CoO$_3$ affects SDW in CoO$_2$ and ultimately glassiness arises. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2004.08319v2-abstract-full').style.display = 'none'; document.getElementById('2004.08319v2-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> 17 October, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 17 April, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 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">7 pages, 8 figures and supplementary file</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Physical Review B 102, 094428 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2004.01406">arXiv:2004.01406</a> <span> [<a href="https://arxiv.org/pdf/2004.01406">pdf</a>, <a href="https://arxiv.org/format/2004.01406">other</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/10.1103/PhysRevB.101.220202">10.1103/PhysRevB.101.220202 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Origin of the high Seebeck coefficient of the misfit [Ca$_2$CoO$_3$]$_{0.62}$[CoO$_2$] cobaltate from site-specific valency and spin-state determinations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Ahad%2C+A">Abdul Ahad</a>, <a href="/search/cond-mat?searchtype=author&query=Gautam%2C+K">K. Gautam</a>, <a href="/search/cond-mat?searchtype=author&query=Majid%2C+S+S">S. S. Majid</a>, <a href="/search/cond-mat?searchtype=author&query=Francoual%2C+S">S. Francoual</a>, <a href="/search/cond-mat?searchtype=author&query=Rahman%2C+F">F. Rahman</a>, <a href="/search/cond-mat?searchtype=author&query=De+Groot%2C+F+M+F">Frank M. F. De Groot</a>, <a href="/search/cond-mat?searchtype=author&query=Shukla%2C+D+K">D. K. Shukla</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="2004.01406v2-abstract-short" style="display: inline;"> Layered misfit cobaltate [Ca$_2$CoO$_3$]$_{0.62}$[CoO$_2$], which emerged as an important thermoelectric material~[A. C. Masset et al. Phys. Rev. B, 62, 166 (2000)], has been explored extensively in the last decade for the exact mechanism behind its high Seebeck coefficient. Its complex crystal and electronic structures have inhibited consensus among such investigations. This situation has arisen… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2004.01406v2-abstract-full').style.display = 'inline'; document.getElementById('2004.01406v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2004.01406v2-abstract-full" style="display: none;"> Layered misfit cobaltate [Ca$_2$CoO$_3$]$_{0.62}$[CoO$_2$], which emerged as an important thermoelectric material~[A. C. Masset et al. Phys. Rev. B, 62, 166 (2000)], has been explored extensively in the last decade for the exact mechanism behind its high Seebeck coefficient. Its complex crystal and electronic structures have inhibited consensus among such investigations. This situation has arisen mainly due to difficulties in accurate identification of the chemical state, spin state, and site symmetries in its two subsystems (rocksalt [Ca$_2$CoO$_3$] and triangular [CoO$_2$]). By employing resonant photoemission spectroscopy and x-ray absorption spectroscopy along with charge transfer multiplet simulations (at the Co ions), we have successfully identified the site symmetries, valencies and spin states of the Co in both layers. Our site-symmetry observations explain the experimental value of the high Seebeck coefficient and also confirm that the carriers hop within the rocksalt layer, which is in contrast to earlier reports where hopping within triangular CoO$_2$ layer has been held responsible for the large Seebeck coefficient. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2004.01406v2-abstract-full').style.display = 'none'; document.getElementById('2004.01406v2-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> 17 June, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 3 April, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 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">5 pages, 4 figures and 1 supplementary with 3 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 101, 220202(R) (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2002.00135">arXiv:2002.00135</a> <span> [<a href="https://arxiv.org/pdf/2002.00135">pdf</a>, <a href="https://arxiv.org/format/2002.00135">other</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="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/PhysRevB.107.214405">10.1103/PhysRevB.107.214405 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Random magnetic anisotropy driven transitions in layered perovskite LaSrCoO$_4$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Ahad%2C+A">Abdul Ahad</a>, <a href="/search/cond-mat?searchtype=author&query=Gautam%2C+K">K. Gautam</a>, <a href="/search/cond-mat?searchtype=author&query=Majid%2C+S+S">S. S. Majid</a>, <a href="/search/cond-mat?searchtype=author&query=Dey%2C+K">K. Dey</a>, <a href="/search/cond-mat?searchtype=author&query=Tripathy%2C+A">A. Tripathy</a>, <a href="/search/cond-mat?searchtype=author&query=Rahman%2C+F">F. Rahman</a>, <a href="/search/cond-mat?searchtype=author&query=Choudhary%2C+R+J">R. J. Choudhary</a>, <a href="/search/cond-mat?searchtype=author&query=Sankar%2C+R">R. Sankar</a>, <a href="/search/cond-mat?searchtype=author&query=Sinha%2C+A+K">A. K. Sinha</a>, <a href="/search/cond-mat?searchtype=author&query=Kaul%2C+S+N">S. N. Kaul</a>, <a href="/search/cond-mat?searchtype=author&query=Shukla%2C+D+K">D. K. Shukla</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="2002.00135v3-abstract-short" style="display: inline;"> Attempts to unravel the nature of magnetic ordering in LaSrCoO$_4$ (Co$^{3+}$), a compound intermediate between antiferromagnetic (AFM) La$_2$CoO$_4$ (Co$^{2+}$) and ferromagnetic (FM) Sr$_2$CoO$_4$ (Co$^{4+}$), have met with a limited success so far. In this report, the results of a thorough investigation of dc magnetization and ac susceptibility (ACS) in single-phase LaSrCoO$_4$ provide clinchin… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2002.00135v3-abstract-full').style.display = 'inline'; document.getElementById('2002.00135v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2002.00135v3-abstract-full" style="display: none;"> Attempts to unravel the nature of magnetic ordering in LaSrCoO$_4$ (Co$^{3+}$), a compound intermediate between antiferromagnetic (AFM) La$_2$CoO$_4$ (Co$^{2+}$) and ferromagnetic (FM) Sr$_2$CoO$_4$ (Co$^{4+}$), have met with a limited success so far. In this report, the results of a thorough investigation of dc magnetization and ac susceptibility (ACS) in single-phase LaSrCoO$_4$ provide clinching evidence for a thermodynamic paramagnetic (PM) - ferromagnetic (FM) phase transition at T$_{c}$ = 220.5 K, followed at lower temperature (T$_{g}$ = 7.7 K) by a transition to the cluster spin glass (CSG) state. Analysis of the low-field Arrott plot isotherms, in the critical region near T$_{c}$, in terms of the Aharony-Pytte scaling equation of state clearly establishes that the PM-FM transition is basically driven by random magnetic anisotropy (RMA). For temperatures below $\approx$ 30 K, large enough RMA destroys long-range FM order by breaking up the infinite FM network into FM clusters of finite size and leads to the formation of a CSG state at temperatures T $\lesssim$ 8 K by promoting freezing of finite FM clusters in random orientations. Increasing strength of the single-ion magnetocrystalline anisotropy (and hence RMA) with decreasing temperature is taken to reflect an increase in the number of low-spin (LS) Co$^{3+}$ ions at the expense of that of high-spin (HS) Co$^{3+}$ ions. At intermediate temperatures (30 K $\lesssim T \lesssim$ 180 K), spin dynamics has contributions from the infinite FM network (fast relaxation governed by a single anisotropy energy barrier) and finite FM clusters (extremely slow stretched exponential relaxation due to hierarchical energy barriers). <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2002.00135v3-abstract-full').style.display = 'none'; document.getElementById('2002.00135v3-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, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 31 January, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 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">23 pages, 9 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 107, 214405 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1908.01125">arXiv:1908.01125</a> <span> [<a href="https://arxiv.org/pdf/1908.01125">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> <p class="title is-5 mathjax"> Non thermal isostructural electrically driven insulator-metal transition and electro-strain in layered cobaltate </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Ahad%2C+A">Abdul Ahad</a>, <a href="/search/cond-mat?searchtype=author&query=Rawat%2C+R">R. Rawat</a>, <a href="/search/cond-mat?searchtype=author&query=Rahman%2C+F">F. Rahman</a>, <a href="/search/cond-mat?searchtype=author&query=Shukla%2C+D+K">D. K. Shukla</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="1908.01125v1-abstract-short" style="display: inline;"> We report here a discovery of electrically driven insulator to metal transition (IMT) and concomitant isostructural volume expansion in the layered cobaltates which otherwise do not exhibit temperature dependent IMT. These findings are demonstrated at macroscopic, microscopic and atomic scales. With application of voltage growth of metallic regions have been observed in the 2D layered La2-xSrxCoO4… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1908.01125v1-abstract-full').style.display = 'inline'; document.getElementById('1908.01125v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1908.01125v1-abstract-full" style="display: none;"> We report here a discovery of electrically driven insulator to metal transition (IMT) and concomitant isostructural volume expansion in the layered cobaltates which otherwise do not exhibit temperature dependent IMT. These findings are demonstrated at macroscopic, microscopic and atomic scales. With application of voltage growth of metallic regions have been observed in the 2D layered La2-xSrxCoO4. Growth of metallic regions is associated with volume increase (strain as high as 0.3%). Non thermal IMT and electro-strain are proposed to be caused by electro-proliferation of the Co3+ high spin states. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1908.01125v1-abstract-full').style.display = 'none'; document.getElementById('1908.01125v1-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 August, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2019. </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">13 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/1908.00371">arXiv:1908.00371</a> <span> [<a href="https://arxiv.org/pdf/1908.00371">pdf</a>, <a href="https://arxiv.org/format/1908.00371">other</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="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/PhysRevB.101.224430">10.1103/PhysRevB.101.224430 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Magnetic and orbital correlations in multiferroic CaMn$_7$O$_{12}$ probed by x-ray resonant elastic scattering </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Gautam%2C+K">K. Gautam</a>, <a href="/search/cond-mat?searchtype=author&query=Majid%2C+S+S">S. S. Majid</a>, <a href="/search/cond-mat?searchtype=author&query=Francoual%2C+S">S. Francoual</a>, <a href="/search/cond-mat?searchtype=author&query=Ahad%2C+A">A. Ahad</a>, <a href="/search/cond-mat?searchtype=author&query=Dey%2C+K">K. Dey</a>, <a href="/search/cond-mat?searchtype=author&query=Rahn%2C+M+C">M. C. Rahn</a>, <a href="/search/cond-mat?searchtype=author&query=Sankar%2C+R">R. Sankar</a>, <a href="/search/cond-mat?searchtype=author&query=Chou%2C+F+C">F. C. Chou</a>, <a href="/search/cond-mat?searchtype=author&query=Shukla%2C+D+K">D. K. Shukla</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="1908.00371v2-abstract-short" style="display: inline;"> The quadruple perovskite CaMn$_7$O$_{12}$ is a topical multiferroic, in which the hierarchy of electronic correlations driving structural distortions, modulated magnetism, and orbital order is not well known and may vary with temperature. x-ray resonant elastic scattering (XRES) provides a momentum-resolved tool to study these phenomena, even in very small single crystals, with valuable informatio… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1908.00371v2-abstract-full').style.display = 'inline'; document.getElementById('1908.00371v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1908.00371v2-abstract-full" style="display: none;"> The quadruple perovskite CaMn$_7$O$_{12}$ is a topical multiferroic, in which the hierarchy of electronic correlations driving structural distortions, modulated magnetism, and orbital order is not well known and may vary with temperature. x-ray resonant elastic scattering (XRES) provides a momentum-resolved tool to study these phenomena, even in very small single crystals, with valuable information encoded in its polarization- and energy-dependence. We present an application of this technique to CaMn$_7$O$_{12}$. By polarization analysis, it is possible to distinguish superstructure reflections associated with magnetic order and orbital order. Given the high momentum resolution, we resolve a previously unknown splitting of an orbital order superstructure peak, associated with a distinct \textit{locked-in} phase at low temperatures. A second set of orbital order superstructure peaks can then be interpreted as a second-harmonic orbital signal. Surprisingly, the intensities of the first- and second-harmonic orbital signal show disparate temperature and polarization dependence. This orbital re-ordering may be driven by an exchange mechanism, that becomes dominant over the Jahn-Teller instability at low temperature. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1908.00371v2-abstract-full').style.display = 'none'; document.getElementById('1908.00371v2-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> 27 June, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 1 August, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2019. </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">6 pages, 4 figures and 1 supplementary with 3 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 101, 224430 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1907.13042">arXiv:1907.13042</a> <span> [<a href="https://arxiv.org/pdf/1907.13042">pdf</a>, <a href="https://arxiv.org/ps/1907.13042">ps</a>, <a href="https://arxiv.org/format/1907.13042">other</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/10.1103/PhysRevB.101.014108">10.1103/PhysRevB.101.014108 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Role of the V-V dimerization in insulator-metal transition and optical transmittance of pure and doped VO2 thin films </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Majid%2C+S+S">S. S. Majid</a>, <a href="/search/cond-mat?searchtype=author&query=Sahu%2C+S+R">S. R. Sahu</a>, <a href="/search/cond-mat?searchtype=author&query=Ahad%2C+A">A. Ahad</a>, <a href="/search/cond-mat?searchtype=author&query=Dey%2C+K">K. Dey</a>, <a href="/search/cond-mat?searchtype=author&query=Gautam%2C+K">K. Gautam</a>, <a href="/search/cond-mat?searchtype=author&query=Rahman%2C+F">F. Rahman</a>, <a href="/search/cond-mat?searchtype=author&query=Behera%2C+P">P. Behera</a>, <a href="/search/cond-mat?searchtype=author&query=Deshpande%2C+U">U. Deshpande</a>, <a href="/search/cond-mat?searchtype=author&query=Sathe%2C+V+G">V. G. Sathe</a>, <a href="/search/cond-mat?searchtype=author&query=Shukla%2C+D+K">D. K. Shukla</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="1907.13042v1-abstract-short" style="display: inline;"> Insulator to metal (IMT) transition (T$_t$ $\sim$ 341 K) in the VO2 accompanies transition from an infrared (IR) transparent to IR opaque phase. Tailoring of the IMT and associated IR switching behavior can offer potential thermochromic applications. Here we report on effects of the W and the Tb doping on the IMT and associated structural, electronic structure and optical properties of the VO2 thi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1907.13042v1-abstract-full').style.display = 'inline'; document.getElementById('1907.13042v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1907.13042v1-abstract-full" style="display: none;"> Insulator to metal (IMT) transition (T$_t$ $\sim$ 341 K) in the VO2 accompanies transition from an infrared (IR) transparent to IR opaque phase. Tailoring of the IMT and associated IR switching behavior can offer potential thermochromic applications. Here we report on effects of the W and the Tb doping on the IMT and associated structural, electronic structure and optical properties of the VO2 thin film. Our results show that the W doping significantly lowers IMT temperature ($\sim$ 292 K to $\sim$ 247 K for 1.3\% W to 3.7\% W) by stabilizing the metallic rutile, $\it{R}$, phase while Tb doping does not alter the IMT temperature much and retains the insulating monoclinic, $\it{M1}$, phase at room temperature. It is observed that the W doping albeit significantly reduces the IR switching temperature but is detrimental to the solar modulation ability, contrary to the Tb doping effects where higher IR switching temperature and solar modulation ability is observed. The IMT behavior, electrical conductivity and IR switching behavior in the W and the Tb doped thin films are found to be directly associated with the spectral changes in the V 3$\it{d_{\|}}$ states. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1907.13042v1-abstract-full').style.display = 'none'; document.getElementById('1907.13042v1-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> 30 July, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2019. </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">11 pages and 11 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 101, 014108 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1907.12746">arXiv:1907.12746</a> <span> [<a href="https://arxiv.org/pdf/1907.12746">pdf</a>, <a href="https://arxiv.org/ps/1907.12746">ps</a>, <a href="https://arxiv.org/format/1907.12746">other</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> <p class="title is-5 mathjax"> Mott-Hubbard insulator-metal transition in the VO2 thin film: A combined XAS and resonant PES study </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/cond-mat?searchtype=author&query=Majid%2C+S+S">S. S. Majid</a>, <a href="/search/cond-mat?searchtype=author&query=Gautam%2C+K">K. Gautam</a>, <a href="/search/cond-mat?searchtype=author&query=Ahad%2C+A">A. Ahad</a>, <a href="/search/cond-mat?searchtype=author&query=Rahman%2C+F">F. Rahman</a>, <a href="/search/cond-mat?searchtype=author&query=Choudhary%2C+R+J">R. J. Choudhary</a>, <a href="/search/cond-mat?searchtype=author&query=De+Groot%2C+F+M+F">Frank M. F. De Groot</a>, <a href="/search/cond-mat?searchtype=author&query=Shukla%2C+D+K">D. K. Shukla</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="1907.12746v1-abstract-short" style="display: inline;"> We have analyzed spectral weight changes in the conduction and the valence band across insulator to metal transition (IMT) in the VO2 thin film using X-ray absorption spectroscopy (XAS) and resonant photoemission spectroscopy (PES). Through temperature dependent XAS and resonant PES measurements we unveil that spectral changes in the d$_{\|}$ states (V 3$\it{d_{x^2-y^2}}$ orbitals) are directly as… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1907.12746v1-abstract-full').style.display = 'inline'; document.getElementById('1907.12746v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1907.12746v1-abstract-full" style="display: none;"> We have analyzed spectral weight changes in the conduction and the valence band across insulator to metal transition (IMT) in the VO2 thin film using X-ray absorption spectroscopy (XAS) and resonant photoemission spectroscopy (PES). Through temperature dependent XAS and resonant PES measurements we unveil that spectral changes in the d$_{\|}$ states (V 3$\it{d_{x^2-y^2}}$ orbitals) are directly associated with temperature dependent electrical conductivity. Due to presence of the strong electron-electron correlations among the d$_{\|}$ states, across IMT, these states are found to exhibit significant intensity variation compared to insignificant changes in the $蟺^{\ast}$ and the $蟽^{\ast}$ states (which are O 2$\it{p}$ hybridized V 3$\it{d}$ $e_g^蟺$ and $e_g^蟽$ states) in the conduction band. Experimentally obtained values of the correlation parameter (U$_{dd}$ $\sim$ 5.1 eV, intra-atomic V 3$\it{d}$ correlations) and crystal field splitting (10 Dq $\sim$ 2.5 eV) values are used to simulate the V $\it{L_{2,3}}$ edge XAS spectra and an agreement between simulated and experimental spectra also manifests strong correlations. These results unravel that the IMT observed in the VO2 thin film is the Mott-Hubbard insulator-metal transition. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1907.12746v1-abstract-full').style.display = 'none'; document.getElementById('1907.12746v1-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> 30 July, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2019. </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">7 pages and 4 figures</span> </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 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