CINXE.COM

<!DOCTYPE html><html lang="en-US"><head><title>Just a moment...</title><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=Edge"><meta name="robots" content="noindex,nofollow"><meta name="viewport" content="width=device-width,initial-scale=1"><style>*{box-sizing:border-box;margin:0;padding:0}html{line-height:1.15;-webkit-text-size-adjust:100%;color:#313131;font-family:system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica Neue,Arial,Noto Sans,sans-serif,Apple Color Emoji,Segoe UI Emoji,Segoe UI Symbol,Noto Color Emoji}body{display:flex;flex-direction:column;height:100vh;min-height:100vh}.main-content{margin:8rem auto;max-width:60rem;padding-left:1.5rem}@media (width <= 720px){.main-content{margin-top:4rem}}.h2{font-size:1.5rem;font-weight:500;line-height:2.25rem}@media (width <= 720px){.h2{font-size:1.25rem;line-height:1.5rem}}#challenge-error-text{background-image:url(data:image/svg+xml;base64,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);background-repeat:no-repeat;background-size:contain;padding-left:34px}@media (prefers-color-scheme:dark){body{background-color:#222;color:#d9d9d9}}</style><meta http-equiv="refresh" content="390"></head><body class="no-js"><div class="main-wrapper" role="main"><div class="main-content"><noscript><div class="h2"><span id="challenge-error-text">Enable JavaScript and cookies to continue</span></div></noscript></div></div><script>(function(){window._cf_chl_opt={cvId: '3',cZone: "journals.aps.org",cType: 'managed',cRay: '917a8e18a8143f6a',cH: 'NzbnoScntzezzsYpWEPDXqcpm_fv.X_DwfVKmqP0EJc-1740516494-1.2.1.1-PiMuOkW2DPFSskOnwwV0Y4pCdpsUqC92.l2UskDKCscgjvyv40yKWn6erUFhlnv4',cUPMDTk: "\/prl\/abstract\/10.1103\/PhysRevLett.78.1396?__cf_chl_tk=AIylTZ9ZDvKcQi6HS5OWDV.EWedmsRWYEEKgvWRuy0Y-1740516494-1.0.1.1-QNG2SfWzT6axU_fx5.ri8m7lu_bPHSuPTghxXg_QHq8",cFPWv: 'b',cITimeS: '1740516494',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "",fa: "\/prl\/abstract\/10.1103\/PhysRevLett.78.1396?__cf_chl_f_tk=AIylTZ9ZDvKcQi6HS5OWDV.EWedmsRWYEEKgvWRuy0Y-1740516494-1.0.1.1-QNG2SfWzT6axU_fx5.ri8m7lu_bPHSuPTghxXg_QHq8",md: "bD5sG6c8e6TsDg.sXu_IbnROdIr_vrrLEbcRGITVp14-1740516494-1.2.1.1-O9fS4k9nD.6l46Q.ep0PzRh8RqPHSKfd0vkVUZ8zjBfkGmrMUZkHbHNvzZNo52hW66dyB_NUQDDithX2J_zvi7DUHbxekuwRBcIJ1lZLxZc8wG17WPeXJN1B_ddyXWiwld5Tl8L_cB0QxLVAqxZ.5r9zRsKKeAOBmoa34PFw7UXjkpQngO4kR__.ocYo7yRzOQch_Rqn4.rsBZ98gLleeVB9vQloif38a58xFJI4WVS.920K1AtNDWHEAMPPWkGb35CpUNETFrn2SOlcuOtxMtADerjINEN.FdEZIV.OSly5FGT8Ojsa.KE0dDKv6yfowg1DKF2UmUDiIxOr7dcfdlrkGvLpXcAADAHJTn8YGdv9Cr3_a9smWg2Uptn5Bl_nSsgbAgCXI8_xq2spjhbfrbIoHzvT_i90G9O.LFp49M95ys7.AHFgTC9MK9kq9VCseqh_bkt7qOoIDTCB4xGA_421jgrwvcpJHTnc1RPSCTejHs2lN_bclfNXxMpiKP74j0VVde2QAru4np.EW0rGSwGVpN5ZkrReJ1rEw9726zYS.V9Scnk6nKwoDJxDnme8r3phrbe96mnDySq5BQCQSTcwHxlfYBBqMbh3KgUOFVqrs.tExduX_Yg2cH4OlDIPNKYb6.JW1cQRbAZ6pRhvhasylD4UNuLkt4ag3A7Pzv4lOGfr_OGND07aaTqlxMr26zjb5w3jLZbNrW0vacIYK6xTkgFjWirO1l.2C9PYtFx0erO7UXO5BIRrt9WYo4mykOLELZ8.7aTEE3cD2AcIyc3EmAGXqyof2j6lT1xqh9Zm0.QeUgSeRSMLvzsMEP6MbviR0qKUiFH73C_hqWbijx8G36UabJdC3c18Xe5m4d0hAirxlKsjpwd.ICQxFKx5joME.W6HtKC93GHCdf_hk496uts3camoT_K.rU0OU0rGbTQUm1A2MiDJjm2A.hyI6wQg9VCqHerVtvx4HwLy1_3qvF6axscyflpgTrpF9D_RVz9r.BU3NDtM3UAJd.gq3lGeITxx7EmmAPJpsZrbso3vFhse9rFbL9U.FmKPDQWuYN2IOLiui9FyZKxlc5qCWBSxZIOe_UZQ7ytjjY7bPJcfIFr4Z1DEgheoF1pqTVNZ0quZyx4Alhu3oHmbNTcq8CCqMaWDUh.xSC8X9Bck8TNRLyPs1yId1v_b75H.lTU7fXrqsCeuiyFw6DJeRw8ne5z1Er_lBTNbQW.FMaoVIY30Xci5OiVWoUZZaEMnFuHJ8TAMYmXA2wjneZrBi51hEsUPj3oohbfN7U7MpQlpxTPaUK1lWlKb_M8HJD8i5yuPNAbC7UwdBEv5FiX8jGr.pI_tNON9y6f9iaqZJjQiEedXOkNqGr3uWLE21._VJ8hzrkvtr3fJZ.xE480HpeKFM_plBRFG5.0hL0FEjZMT9CRUSavlEckUT.g.UizzTU_f8kw1FMhjYNcHfmg5orQ9OxJ7_k0GytUcaVmZWz9jtpBBTBKQw9LwXySwrxGrX3E.PM_yW.vWYKCQSO0sJNLONQD2DfuRQwev1uxMTktZOTcbIBssc0FxUXy9sgt6hAgAKfPQZD4PeWSwsL9yp5t0NXwWI65eRcmU7DFLj82Chl71.in3SkpeGnOdfgDfNirXOqJzVnBa8WB1g6WusGLkpRH7WOlR3JaomQxRKrLvkx_DppDXoX1S0oEielkNjh8dXak3K_sEMhfgV4MTn7KF52PFIQWrXjJhS1klMg6Ue7ryFVuHjtnsvUETGJzpWMCTaWZppdGF2S5f9I3.Gjh4k0P61Yg26Y2nMhDZG5FfrrnCqIAlupSU4zdSV67N5JbnuhoTNrR9uHKqKDdsdi8pUZpTsQx0OokMVj2rkuPHCrzv.Vsi7aLXP2135JfZrNfQNNkrRAzOXmdxetw5b80Ks0jyVTPwJseHZStD.43wWipfHmNJUaYng54OQIJtPnvwbYT5zjTd379NWhyBGblR1sZNQBrXLbZA_nuSC6hlyMoTaSGJ4TkJ7gYfuTptCg18Plwt6wVq4NId.cO2qbZEataXuahvooGkUHSlizbcbdyjmjXus6bJqIclYU.dfUCG3nGOxyfh67xfbTgNiFW1HlRMeDxzzwH1hGleqVgTxRtJa.7J9XZpovl1FwzRFDhZeZ6S4cAi1xDfIRqrgYzZ6CnyJb8lMpuWSO9Vy94r2X0.KWSyr2AXtLHEuspH2CGNsoB64hohmAGKGf1oY8XbDqpet4hVvdRlMm98B6UYl94iRrxaYO6KtQFuynb6M36gW3d2noKQLcQw1c5g3EbgL4hE_jYt6Os4fseZU8YzzqDLKg8c1TyqD2AtR3yboQsvfevMDAF.1nipbU4kiKimk8ztycZBPeVa4bo8bNaKM24pvYCDVMgwe5hfmI6rBnTs3_KbIIrO5uool5gzUaukG1jClgNgpN2PNspOjBMVQYsh1isy0VtfB7MV_dzZ309yNSLj_3qdvJk4ejZp6k6shacY4k3vWqlQTL9FmYo53Hpv0aEgEKD.xuVSEXEroQ7ZME2GGUX_2kLEA5LJvxfVmsK9Mn2GV4UrEIUL4v0axXYzTtmeziNGrVPRa4v6mKU",mdrd: "Ggs7mI5f5nwPc2vbmoZgLv_wN25nWy1uvDfTkkOJxSg-1740516494-1.2.1.1-fj6VylpB_u.gct8CmwRtNPg_gCA8o5rrkVQBVK.6kicH_Vra.LPNbhsEgGjP758JXe6GE87kDZlt8_4EqjYJt7mlhVRXHrt0nZa_31Bqgvph_Ikm6jsegwMkFUDlDOONk1axW.hIaCFJr_W9sMUl3mubjfJzOGgCAAYDHMTr6w7RbQU0kXuvqbGfamK4d2CmGhwKFbgDvwdHmNnjHOEm4gcOXbrvQa9m2f8v0oTKPgpNCQhX1tS0WiBYptnFWUW6QZM_YCCzPHNgc7fntGMzn7RjPaONq01RSNRyl.O2Q4RQZQPni9uj73i5eT3SZE_.dhFPF.sivk5QopKR9XHHNDM5x8VwCVCEm_LUC2Qu16rSkqJxmVTy9Sw3LGRgeELF_VMB3PNZwo7q8cg8eBIS9miGTZUyZyxWrZugxD3qeZV.sDvvUNpNELO5W0Am7T0mvv_WyBn30OMIPoNdyccF4JuXAuSDASw8lk1t7kbGcTLW4_CsAMmSbtjJ2CBGsCT3wAak0Lmm3xL4kAauUXB.m2HO8ekd10HpU0tWFy1GJISJ9X3CwfLIemJBfMcp4uuowN_L6tPY0ly1jzKIHkzmOzxzBKGfSQr4UwtBKBKqL_7LOMN110gYaWTMDNjOFXRw2YAl52.uVaAP3C6IYE0ckTYQ7S3BvEFXRwxufZKQdyffgOxZYanrIJHv0Z7Kq1E7wy2xgSgBQTb6N1cPndrji7FupEPezC766yqacNTEblEzwPF0FaUOmIzQCEwmHKOvbKeR8Wr.6mr0bM6LB11RDXCAH3Wr8PoWajMGGUGHAEZ6tlYH8gpn.8NKBLSoOXjXYYJD8bNzOmZEQcf7.BFvK6SkRSMZCNHK7Ip8_YpXISHm5wgw9T5RSMiq8dpeDbCszMSwFlZJBzGXR4VFesk2A0NqDWZS8WPX6NG_qgbNRl6v8pYMylCMRk0d9kFNMQAQdnLRz_2UMeTyJPE0vqVyKoQttHeKa8vq2HTY8_SbcEFt07EMGwxzzJBtTxYAou.bhhQnDjRAzDGLHH7P9nGdo9BafwnWePZ80H.jz1KKURJ5EWU7JQlbYOcs9HzbgVOMqivPOD8uP6LROVqcpQWhqsvlXc.5y3MScGIqqFBfPnAGeeOqcTY2EIFsXkHiXNVPP9R9Hpuc.w8Pz6cCjWB69c2wyXM1em58Z8Py1iXiA3w5dnKvSv8OA.UDkE.q_a.7B3DA99UcS4YYsyiZ_oB_BwJRJCB_EXLusZR.6gR70nDbO7Zn3tVoV7gRDej_3KzNsQ2a0b1B28Q26.TSWMAbwP35WnRaeDMjKcqvElQYy9pIW1I_ZyyBnJkwAKbzldkuBFuhe_Z7aMJnwRgEE.tRzRVPNJIEQV86T__4prlhjwdTqdQrTs6RjJ6yqE5_MushdbB9oGp9srvYbi._fK3e_PVU2js8I3kWdFpkhwDNl5O9wbWKDuRBqe.y_qbRpG6RZrEX5Sh44XT7s0tLtBWwMG7TQiaoXYlP39YkMyoip6Ig82M3JRe7Mqj4pYmt3995l0tNZijWr5Rt128Vf0_mIv7NuuDLQzzkeuy6Y8T_Cbo8aKhMsZLEAhZ5ZBkdPHZDVY0sUCykDlvqKm3Vw8b3AWkYAOqd5tDp6V8otLUhD2bl84Ou38hI0vBZ0cgR1k6Pil9YYRw.6OGE4xlPrf5ke.2rxoEn6GPtpTmtg5FJ.XiqOG_AZAXdUJ7xMZ30sOjlEC2ujScW.h_y4xfgLgJZYyHTKL64XD6rI6yigXkm2kv31in1CwVMOT03fC8LdbcRxUzC5pFITgUCCqSfjcydowD5VASddZf.w0OqbRDsmhJ5FEDwMFnJQwJy3jOU1Bub2Y945wMKYbZIzYwOrfMewTs85DtzW8AKklzY1P7vdXF3NuH_IWUxjFPvOOy1jvi6Ow7MyUvkRyKviC_2d4xF5lwMALYR.QssMBypMM4yZWKXmVIkE4CUzx3pikoSUiGbKIUE0Zvp6ObP7pa_8hcbeQ"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=917a8e18a8143f6a';window._cf_chl_opt.cOgUHash = location.hash === '' && location.href.indexOf('#') !== -1 ? '#' : location.hash;window._cf_chl_opt.cOgUQuery = location.search === '' && location.href.slice(0, location.href.length - window._cf_chl_opt.cOgUHash.length).indexOf('?') !== -1 ? '?' : location.search;if (window.history && window.history.replaceState) {var ogU = location.pathname + window._cf_chl_opt.cOgUQuery + window._cf_chl_opt.cOgUHash;history.replaceState(null, null, "\/prl\/abstract\/10.1103\/PhysRevLett.78.1396?__cf_chl_rt_tk=AIylTZ9ZDvKcQi6HS5OWDV.EWedmsRWYEEKgvWRuy0Y-1740516494-1.0.1.1-QNG2SfWzT6axU_fx5.ri8m7lu_bPHSuPTghxXg_QHq8" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>