The magnetization dynamics of two skyrmions with antiparallel vortex rotations on a nanowire substrate were investigated using micromagnetic simulations. When positioned in proximity, the skyrmions exhibit attractive interactions that decrease their separation distance. This interaction leads to a magnetic energy transition, resulting in the fusion of the two skyrmions into a single connected entity. Applying a static magnetic field aligned with the magnetization direction of the skyrmion cores causes this connected structure to expand, increasing the distance between their cores. Conversely, exposing the connected skyrmions to a specific alternating magnetic field induces resonant oscillations in the core-to-core distance, with the resonance frequency decreasing as the field amplitude increases. The effective mass of the connected skyrmions at resonance is calculated using the resonance frequency. Notably, excessively high amplitudes can cause these oscillations to converge the skyrmions excessively, leading to their annihilation. In simulations involving both static and alternating magnetic fields, separation of the connected skyrmions was not observed. These findings have potential implications for the advancement of technologies utilizing skyrmion numbers for innovative applications.
{"title":"Interconnected skyrmions in a nanowire structure: Micromagnetic simulations","authors":"Taichi Nishitani, Syuta Honda, Hiroyoshi Itoh, Tomokatsu Ohsawa, Masaaki A. Tanaka","doi":"10.1103/physrevb.110.174415","DOIUrl":"https://doi.org/10.1103/physrevb.110.174415","url":null,"abstract":"The magnetization dynamics of two skyrmions with antiparallel vortex rotations on a nanowire substrate were investigated using micromagnetic simulations. When positioned in proximity, the skyrmions exhibit attractive interactions that decrease their separation distance. This interaction leads to a magnetic energy transition, resulting in the fusion of the two skyrmions into a single connected entity. Applying a static magnetic field aligned with the magnetization direction of the skyrmion cores causes this connected structure to expand, increasing the distance between their cores. Conversely, exposing the connected skyrmions to a specific alternating magnetic field induces resonant oscillations in the core-to-core distance, with the resonance frequency decreasing as the field amplitude increases. The effective mass of the connected skyrmions at resonance is calculated using the resonance frequency. Notably, excessively high amplitudes can cause these oscillations to converge the skyrmions excessively, leading to their annihilation. In simulations involving both static and alternating magnetic fields, separation of the connected skyrmions was not observed. These findings have potential implications for the advancement of technologies utilizing skyrmion numbers for innovative applications.","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"150 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142597315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-08DOI: 10.1103/physrevb.110.184508
Pavel D. Kurilovich, Vladislav D. Kurilovich, Aleksandr E. Svetogorov, Wolfgang Belzig, Michel H. Devoret, Leonid I. Glazman
A mechanism to deterministically prepare a nanowire Josephson junction in an odd parity state is proposed. The mechanism involves population of two Andreev levels by a resonant microwave drive breaking a Cooper pair, and a subsequent ionization of one of the levels by the same drive. Robust preparation of the odd state is allowed by a residual Coulomb repulsion in the junction. A similar resonant process can also be used to prepare the junction in the even state. Our theory explains a recent experiment [J. J. Wesdorp et al., Phys. Rev. Lett.131, 117001 (2023)].
本文提出了一种以确定方式制备奇奇偶态纳米线约瑟夫森结的机制。该机制包括通过打破库珀对的共振微波驱动产生两个安德烈耶夫电平，以及随后通过相同的驱动使其中一个电平电离。结内残余的库仑斥力允许奇数态的稳健制备。类似的共振过程也可以用来制备偶态的结。我们的理论解释了最近的一项实验[J. J. Wesdorp 等人，Phys. Rev. Lett. 131, 117001 (2023)]。
{"title":"On-demand population of Andreev levels by their ionization in the presence of Coulomb blockade","authors":"Pavel D. Kurilovich, Vladislav D. Kurilovich, Aleksandr E. Svetogorov, Wolfgang Belzig, Michel H. Devoret, Leonid I. Glazman","doi":"10.1103/physrevb.110.184508","DOIUrl":"https://doi.org/10.1103/physrevb.110.184508","url":null,"abstract":"A mechanism to deterministically prepare a nanowire Josephson junction in an odd parity state is proposed. The mechanism involves population of two Andreev levels by a resonant microwave drive breaking a Cooper pair, and a subsequent ionization of one of the levels by the same drive. Robust preparation of the odd state is allowed by a residual Coulomb repulsion in the junction. A similar resonant process can also be used to prepare the junction in the even state. Our theory explains a recent experiment [J. J. Wesdorp <i>et al.</i>, <span>Phys. Rev. Lett.</span> <b>131</b>, 117001 (2023)].","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"35 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142597326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-07DOI: 10.1103/physrevb.110.205118
Jasmine K. Hinton, Daniel Schacher, Wonseok Lee, G. Alexander Smith, Emily Siska, Changyong Park, Paul B. Ellison, Scott K. Cushing, Craig P. Schwartz, Keith V. Lawler, Ashkan Salamat
An electronic topological transition (ETT) in cadmium below 1 GPa is investigated in situ with experimental x-ray absorption spectroscopy and projecting calculated core-valence excitons onto the band structure. These projections are a useful application of the Bethe-Salpeter equation approach that considers many-body effects. The method described herein can be used for systems that are otherwise difficult to probe in situ; therefore, it provides a generalizable approach to identifying and understanding ETTs under high pressure. Although pressure-induced ETTs are often probed using indirect structural responses, our own x-ray diffraction and Raman studies suggest a second-order structural transition around 3 GPa but are largely insensitive to or inconclusive for the previously studied ETT in this region.
通过实验 X 射线吸收光谱和将计算出的核价激子投射到能带结构上，对低于 1 GPa 的镉电子拓扑转变 (ETT) 进行了现场研究。这些投影是考虑多体效应的 Bethe-Salpeter 方程方法的有用应用。本文描述的方法可用于难以进行原位探测的系统；因此，它为识别和理解高压下的 ETT 提供了一种可推广的方法。虽然压力诱导的 ETT 通常使用间接结构响应进行探测，但我们自己的 X 射线衍射和拉曼研究表明，在 3 GPa 附近存在二阶结构转变，但对之前研究的该区域的 ETT 基本不敏感或没有结论。
{"title":"Electronic topological transitions in cadmium under pressure studied via theoretical and experimental x-ray absorption spectroscopy","authors":"Jasmine K. Hinton, Daniel Schacher, Wonseok Lee, G. Alexander Smith, Emily Siska, Changyong Park, Paul B. Ellison, Scott K. Cushing, Craig P. Schwartz, Keith V. Lawler, Ashkan Salamat","doi":"10.1103/physrevb.110.205118","DOIUrl":"https://doi.org/10.1103/physrevb.110.205118","url":null,"abstract":"An electronic topological transition (ETT) in cadmium below 1 GPa is investigated <i>in situ</i> with experimental x-ray absorption spectroscopy and projecting calculated core-valence excitons onto the band structure. These projections are a useful application of the Bethe-Salpeter equation approach that considers many-body effects. The method described herein can be used for systems that are otherwise difficult to probe <i>in situ</i>; therefore, it provides a generalizable approach to identifying and understanding ETTs under high pressure. Although pressure-induced ETTs are often probed using indirect structural responses, our own x-ray diffraction and Raman studies suggest a second-order structural transition around 3 GPa but are largely insensitive to or inconclusive for the previously studied ETT in this region.","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"95 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142597402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-07DOI: 10.1103/physrevb.110.174413
Alexey B. Ustinov, Leonid S. Vedernikov, Ivan Y. Tatsenko, Andrey A. Stashkevich
This paper reports an experimental demonstration of efficient excitation of fundamental dark spin wave solitons on a magnonic active ring below self-oscillation threshold by means of a biharmonic technique. This technique is shown to be especially appropriate for implementing multisoliton regimes otherwise unattainable. Theoretical analysis has revealed a very important role played by the phase relations between individual harmonics generated nonlinearly in the process of the formation of multiple solitons. The proposed ad hoc approach making use of the inverse Fourier transform has allowed us to elucidate the mechanisms underlying the formation of investigated nonlinear waveforms from their power spectra.
{"title":"Excitation of fundamental multiple dark solitons from forced biharmonic oscillations in a magnonic active ring","authors":"Alexey B. Ustinov, Leonid S. Vedernikov, Ivan Y. Tatsenko, Andrey A. Stashkevich","doi":"10.1103/physrevb.110.174413","DOIUrl":"https://doi.org/10.1103/physrevb.110.174413","url":null,"abstract":"This paper reports an experimental demonstration of efficient excitation of fundamental dark spin wave solitons on a magnonic active ring below self-oscillation threshold by means of a biharmonic technique. This technique is shown to be especially appropriate for implementing multisoliton regimes otherwise unattainable. Theoretical analysis has revealed a very important role played by the phase relations between individual harmonics generated nonlinearly in the process of the formation of multiple solitons. The proposed <i>ad hoc</i> approach making use of the inverse Fourier transform has allowed us to elucidate the mechanisms underlying the formation of investigated nonlinear waveforms from their power spectra.","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"37 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142597339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-07DOI: 10.1103/physrevb.110.184505
O. Kashuba, R.-P. Riwar
The inherent complexity of system-bath interactions often requires making critical approximations, which we here show to have a radical influence on the renormalization group flow and the resulting phase diagram. Specifically, for the Caldeira-Leggett model Schmid and Bulgadaev (SB) predicted a phase transition, whose experimental verification in resistive superconducting circuits is currently hotly debated. For normal metal and Josephson junction array resistors, we show that the mapping to Caldeira-Leggett is only exact when applying approximations which decompactify the superconducting phase. We show that there exist treatments that retain phase compactness, which immediately lead to a phase diagram depending on four instead of two parameters. While we still find an SB-like transition in the transmon regime, the critical parameter is controlled exclusively by the capacitive coupling. In contrast, the Cooper pair box maps to the anisotropic Kondo model, where a pseudoferromagnetic phase is not allowed for regular electrostatic interactions.
{"title":"Limitations of Caldeira-Leggett model for description of phase transitions in superconducting circuits","authors":"O. Kashuba, R.-P. Riwar","doi":"10.1103/physrevb.110.184505","DOIUrl":"https://doi.org/10.1103/physrevb.110.184505","url":null,"abstract":"The inherent complexity of system-bath interactions often requires making critical approximations, which we here show to have a radical influence on the renormalization group flow and the resulting phase diagram. Specifically, for the Caldeira-Leggett model Schmid and Bulgadaev (SB) predicted a phase transition, whose experimental verification in resistive superconducting circuits is currently hotly debated. For normal metal and Josephson junction array resistors, we show that the mapping to Caldeira-Leggett is only exact when applying approximations which decompactify the superconducting phase. We show that there exist treatments that retain phase compactness, which immediately lead to a phase diagram depending on four instead of two parameters. While we still find an SB-like transition in the transmon regime, the critical parameter is controlled exclusively by the capacitive coupling. In contrast, the Cooper pair box maps to the anisotropic Kondo model, where a pseudoferromagnetic phase is not allowed for regular electrostatic interactions.","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"80 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142597341","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-07DOI: 10.1103/physrevb.110.184402
J. Khatua, M. Gomilšek, Kwang-Yong Choi, P. Khuntia
Quantum magnets based on honeycomb lattices with a low coordination number offer a viable ground to realize exotic emergent quantum excitations and phenomena arising from the interplay between competing magnetic interactions, spin correlations, and spatial anisotropy. However, unlike their low-spin analogs, high-spin honeycomb lattice antiferromagnets have remained comparatively less explored in the context of capturing the classical limits of quantum phenomena. Herein, we report the crystal structure, magnetic susceptibility, specific heat, and electron spin resonance (ESR) measurements, complemented by <i>ab initio</i> density functional theory (DFT) calculations, on polycrystalline samples of <mjx-container ctxtmenu_counter="81" ctxtmenu_oldtabindex="1" jax="CHTML" overflow="linebreak" role="tree" sre-explorer- style="font-size: 100.7%;" tabindex="0"><mjx-math data-semantic-structure="(7 (2 0 1) 6 (5 3 4))"><mjx-mrow data-semantic-annotation="clearspeak:unit" data-semantic-children="2,5" data-semantic-content="6" data-semantic- data-semantic-owns="2 6 5" data-semantic-role="implicit" data-semantic-speech="upper F e upper P 3 upper S i upper O 11" data-semantic-type="infixop"><mjx-msub data-semantic-children="0,1" data-semantic- data-semantic-owns="0 1" data-semantic-parent="7" data-semantic-role="unknown" data-semantic-type="subscript"><mjx-mi data-semantic-font="normal" data-semantic- data-semantic-parent="2" data-semantic-role="unknown" data-semantic-type="identifier"><mjx-c noic="true" style="padding-top: 0.657em;">F</mjx-c><mjx-c noic="true" style="padding-top: 0.657em;">e</mjx-c><mjx-c style="padding-top: 0.657em;">P</mjx-c></mjx-mi><mjx-script style="vertical-align: -0.15em;"><mjx-mn data-semantic-annotation="clearspeak:simple" data-semantic-font="normal" data-semantic- data-semantic-parent="2" data-semantic-role="integer" data-semantic-type="number" size="s"><mjx-c>3</mjx-c></mjx-mn></mjx-script></mjx-msub><mjx-mo data-semantic-added="true" data-semantic- data-semantic-operator="infixop," data-semantic-parent="7" data-semantic-role="multiplication" data-semantic-type="operator"><mjx-c></mjx-c></mjx-mo><mjx-msub data-semantic-children="3,4" data-semantic- data-semantic-owns="3 4" data-semantic-parent="7" data-semantic-role="unknown" data-semantic-type="subscript" space="2"><mjx-mi data-semantic-font="normal" data-semantic- data-semantic-parent="5" data-semantic-role="unknown" data-semantic-type="identifier"><mjx-c noic="true" style="padding-top: 0.673em;">S</mjx-c><mjx-c noic="true" style="padding-top: 0.673em;">i</mjx-c><mjx-c style="padding-top: 0.673em;">O</mjx-c></mjx-mi><mjx-script style="vertical-align: -0.15em;"><mjx-mn data-semantic-annotation="clearspeak:simple" data-semantic-font="normal" data-semantic- data-semantic-parent="5" data-semantic-role="integer" data-semantic-type="number" size="s"><mjx-c noic="true" style="padding-top: 0.639em;">1</mjx-c><mjx-c style="padding-top: 0.639em;">1</mjx-c></mjx-mn></mjx-script></mjx-msu
{"title":"Magnetism and field-induced effects in the𝑆=52honeycomb lattice antiferromagnetFeP3SiO11","authors":"J. Khatua, M. Gomilšek, Kwang-Yong Choi, P. Khuntia","doi":"10.1103/physrevb.110.184402","DOIUrl":"https://doi.org/10.1103/physrevb.110.184402","url":null,"abstract":"Quantum magnets based on honeycomb lattices with a low coordination number offer a viable ground to realize exotic emergent quantum excitations and phenomena arising from the interplay between competing magnetic interactions, spin correlations, and spatial anisotropy. However, unlike their low-spin analogs, high-spin honeycomb lattice antiferromagnets have remained comparatively less explored in the context of capturing the classical limits of quantum phenomena. Herein, we report the crystal structure, magnetic susceptibility, specific heat, and electron spin resonance (ESR) measurements, complemented by <i>ab initio</i> density functional theory (DFT) calculations, on polycrystalline samples of <mjx-container ctxtmenu_counter=\"81\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" overflow=\"linebreak\" role=\"tree\" sre-explorer- style=\"font-size: 100.7%;\" tabindex=\"0\"><mjx-math data-semantic-structure=\"(7 (2 0 1) 6 (5 3 4))\"><mjx-mrow data-semantic-annotation=\"clearspeak:unit\" data-semantic-children=\"2,5\" data-semantic-content=\"6\" data-semantic- data-semantic-owns=\"2 6 5\" data-semantic-role=\"implicit\" data-semantic-speech=\"upper F e upper P 3 upper S i upper O 11\" data-semantic-type=\"infixop\"><mjx-msub data-semantic-children=\"0,1\" data-semantic- data-semantic-owns=\"0 1\" data-semantic-parent=\"7\" data-semantic-role=\"unknown\" data-semantic-type=\"subscript\"><mjx-mi data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"2\" data-semantic-role=\"unknown\" data-semantic-type=\"identifier\"><mjx-c noic=\"true\" style=\"padding-top: 0.657em;\">F</mjx-c><mjx-c noic=\"true\" style=\"padding-top: 0.657em;\">e</mjx-c><mjx-c style=\"padding-top: 0.657em;\">P</mjx-c></mjx-mi><mjx-script style=\"vertical-align: -0.15em;\"><mjx-mn data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"2\" data-semantic-role=\"integer\" data-semantic-type=\"number\" size=\"s\"><mjx-c>3</mjx-c></mjx-mn></mjx-script></mjx-msub><mjx-mo data-semantic-added=\"true\" data-semantic- data-semantic-operator=\"infixop,\" data-semantic-parent=\"7\" data-semantic-role=\"multiplication\" data-semantic-type=\"operator\"><mjx-c></mjx-c></mjx-mo><mjx-msub data-semantic-children=\"3,4\" data-semantic- data-semantic-owns=\"3 4\" data-semantic-parent=\"7\" data-semantic-role=\"unknown\" data-semantic-type=\"subscript\" space=\"2\"><mjx-mi data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"5\" data-semantic-role=\"unknown\" data-semantic-type=\"identifier\"><mjx-c noic=\"true\" style=\"padding-top: 0.673em;\">S</mjx-c><mjx-c noic=\"true\" style=\"padding-top: 0.673em;\">i</mjx-c><mjx-c style=\"padding-top: 0.673em;\">O</mjx-c></mjx-mi><mjx-script style=\"vertical-align: -0.15em;\"><mjx-mn data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"5\" data-semantic-role=\"integer\" data-semantic-type=\"number\" size=\"s\"><mjx-c noic=\"true\" style=\"padding-top: 0.639em;\">1</mjx-c><mjx-c style=\"padding-top: 0.639em;\">1</mjx-c></mjx-mn></mjx-script></mjx-msu","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"244 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142597344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-07DOI: 10.1103/physrevb.110.205116
I. V. Solovyev, R. Ono, S. A. Nikolaev
The exchange interactions in insulators depend on the orbital state of magnetic ions, obeying certain phenomenological principles, known as Goodenough-Kanamori-Anderson rules. Particularly, the ferro order of alike orbitals tends to stabilize antiferromagnetic interactions, while the antiferro order of unlike orbitals favors ferromagnetic interactions. The Kugel-Khomskii theory provides a universal view on such coupling between spin and orbital degrees of freedom, based on the superexchange processes: namely, for a given magnetic order, the occupied orbitals tend to arrange in a way to further minimize the exchange energy. Then, if two magnetic sites are connected by the spatial inversion, the antiferro orbital order should lead to the ferromagnetic coupling <i>and</i> break the inversion symmetry. This constitutes the basic idea of our work, which provides a pathway for designing ferromagnetic ferroelectrics: the rare but fundamentally and practically important multiferroic materials. After illustrating the basic idea on toy-model examples, we propose that such behavior can be indeed realized in the van der Waals ferromagnet <mjx-container ctxtmenu_counter="652" ctxtmenu_oldtabindex="1" jax="CHTML" overflow="linebreak" role="tree" sre-explorer- style="font-size: 100.7%;" tabindex="0"><mjx-math data-semantic-structure="(2 0 1)"><mjx-msub data-semantic-children="0,1" data-semantic- data-semantic-owns="0 1" data-semantic-role="unknown" data-semantic-speech="upper V upper I 3" data-semantic-type="subscript"><mjx-mi data-semantic-font="normal" data-semantic- data-semantic-parent="2" data-semantic-role="unknown" data-semantic-type="identifier"><mjx-c noic="true" style="padding-top: 0.657em;">V</mjx-c><mjx-c style="padding-top: 0.657em;">I</mjx-c></mjx-mi><mjx-script style="vertical-align: -0.15em;"><mjx-mn data-semantic-annotation="clearspeak:simple" data-semantic-font="normal" data-semantic- data-semantic-parent="2" data-semantic-role="integer" data-semantic-type="number" size="s"><mjx-c>3</mjx-c></mjx-mn></mjx-script></mjx-msub></mjx-math></mjx-container>, employing for this analysis the realistic model derived from first-principles calculations for magnetic <mjx-container ctxtmenu_counter="653" ctxtmenu_oldtabindex="1" jax="CHTML" overflow="linebreak" role="tree" sre-explorer- style="font-size: 100.7%;" tabindex="0"><mjx-math data-semantic-structure="(3 0 2 1)"><mjx-mrow data-semantic-annotation="clearspeak:simple;clearspeak:unit" data-semantic-children="0,1" data-semantic-content="2" data-semantic- data-semantic-owns="0 2 1" data-semantic-role="implicit" data-semantic-speech="3 d" data-semantic-type="infixop"><mjx-mn data-semantic-annotation="clearspeak:simple" data-semantic-font="normal" data-semantic- data-semantic-parent="3" data-semantic-role="integer" data-semantic-type="number"><mjx-c>3</mjx-c></mjx-mn><mjx-mo data-semantic-added="true" data-semantic- data-semantic-operator="infixop," data-semantic-parent="3" data-semantic-role="multiplicat
{"title":"Ferromagnetic ferroelectricity due to the Kugel-Khomskii mechanism of orbital ordering assisted by atomic Hund's second rule effects","authors":"I. V. Solovyev, R. Ono, S. A. Nikolaev","doi":"10.1103/physrevb.110.205116","DOIUrl":"https://doi.org/10.1103/physrevb.110.205116","url":null,"abstract":"The exchange interactions in insulators depend on the orbital state of magnetic ions, obeying certain phenomenological principles, known as Goodenough-Kanamori-Anderson rules. Particularly, the ferro order of alike orbitals tends to stabilize antiferromagnetic interactions, while the antiferro order of unlike orbitals favors ferromagnetic interactions. The Kugel-Khomskii theory provides a universal view on such coupling between spin and orbital degrees of freedom, based on the superexchange processes: namely, for a given magnetic order, the occupied orbitals tend to arrange in a way to further minimize the exchange energy. Then, if two magnetic sites are connected by the spatial inversion, the antiferro orbital order should lead to the ferromagnetic coupling <i>and</i> break the inversion symmetry. This constitutes the basic idea of our work, which provides a pathway for designing ferromagnetic ferroelectrics: the rare but fundamentally and practically important multiferroic materials. After illustrating the basic idea on toy-model examples, we propose that such behavior can be indeed realized in the van der Waals ferromagnet <mjx-container ctxtmenu_counter=\"652\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" overflow=\"linebreak\" role=\"tree\" sre-explorer- style=\"font-size: 100.7%;\" tabindex=\"0\"><mjx-math data-semantic-structure=\"(2 0 1)\"><mjx-msub data-semantic-children=\"0,1\" data-semantic- data-semantic-owns=\"0 1\" data-semantic-role=\"unknown\" data-semantic-speech=\"upper V upper I 3\" data-semantic-type=\"subscript\"><mjx-mi data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"2\" data-semantic-role=\"unknown\" data-semantic-type=\"identifier\"><mjx-c noic=\"true\" style=\"padding-top: 0.657em;\">V</mjx-c><mjx-c style=\"padding-top: 0.657em;\">I</mjx-c></mjx-mi><mjx-script style=\"vertical-align: -0.15em;\"><mjx-mn data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"2\" data-semantic-role=\"integer\" data-semantic-type=\"number\" size=\"s\"><mjx-c>3</mjx-c></mjx-mn></mjx-script></mjx-msub></mjx-math></mjx-container>, employing for this analysis the realistic model derived from first-principles calculations for magnetic <mjx-container ctxtmenu_counter=\"653\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" overflow=\"linebreak\" role=\"tree\" sre-explorer- style=\"font-size: 100.7%;\" tabindex=\"0\"><mjx-math data-semantic-structure=\"(3 0 2 1)\"><mjx-mrow data-semantic-annotation=\"clearspeak:simple;clearspeak:unit\" data-semantic-children=\"0,1\" data-semantic-content=\"2\" data-semantic- data-semantic-owns=\"0 2 1\" data-semantic-role=\"implicit\" data-semantic-speech=\"3 d\" data-semantic-type=\"infixop\"><mjx-mn data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"3\" data-semantic-role=\"integer\" data-semantic-type=\"number\"><mjx-c>3</mjx-c></mjx-mn><mjx-mo data-semantic-added=\"true\" data-semantic- data-semantic-operator=\"infixop,\" data-semantic-parent=\"3\" data-semantic-role=\"multiplicat","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"446 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142598161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-07DOI: 10.1103/physrevb.110.174105
Sebastian Bichelmaier, Jesús Carrete, Georg K. H. Madsen
The advances of machine-learned force fields have opened up molecular dynamics (MD) simulations for compounds for which <i>ab initio</i> MD is too resource intensive and phenomena for which classical force fields are insufficient. Here we describe a neural-network force field parametrized to reproduce the <mjx-container ctxtmenu_counter="23" ctxtmenu_oldtabindex="1" jax="CHTML" overflow="linebreak" role="tree" sre-explorer- style="font-size: 100.7%;" tabindex="0"><mjx-math data-semantic-structure="(5 (2 0 1) 4 3)"><mjx-mrow data-semantic-annotation="clearspeak:unit" data-semantic-children="2,3" data-semantic-content="4" data-semantic- data-semantic-owns="2 4 3" data-semantic-role="implicit" data-semantic-speech="normal r squared upper S upper C upper A upper N" data-semantic-type="infixop"><mjx-msup data-semantic-children="0,1" data-semantic- data-semantic-owns="0 1" data-semantic-parent="5" data-semantic-role="latinletter" data-semantic-type="superscript"><mjx-mrow><mjx-mi data-semantic-annotation="clearspeak:simple" data-semantic-font="normal" data-semantic- data-semantic-parent="2" data-semantic-role="latinletter" data-semantic-type="identifier"><mjx-c>r</mjx-c></mjx-mi></mjx-mrow><mjx-script style="vertical-align: 0.363em;"><mjx-mn data-semantic-annotation="clearspeak:simple" data-semantic-font="normal" data-semantic- data-semantic-parent="2" data-semantic-role="integer" data-semantic-type="number" size="s"><mjx-c>2</mjx-c></mjx-mn></mjx-script></mjx-msup><mjx-mo data-semantic-added="true" data-semantic- data-semantic-operator="infixop," data-semantic-parent="5" data-semantic-role="multiplication" data-semantic-type="operator"><mjx-c></mjx-c></mjx-mo><mjx-mi data-semantic-font="normal" data-semantic- data-semantic-parent="5" data-semantic-role="unknown" data-semantic-type="identifier" space="2"><mjx-c noic="true" style="padding-top: 0.669em;">S</mjx-c><mjx-c noic="true" style="padding-top: 0.669em;">C</mjx-c><mjx-c noic="true" style="padding-top: 0.669em;">A</mjx-c><mjx-c style="padding-top: 0.669em;">N</mjx-c></mjx-mi></mjx-mrow></mjx-math></mjx-container> potential energy landscape of <mjx-container ctxtmenu_counter="24" ctxtmenu_oldtabindex="1" jax="CHTML" overflow="linebreak" role="tree" sre-explorer- style="font-size: 100.7%;" tabindex="0"><mjx-math data-semantic-structure="(2 0 1)"><mjx-msub data-semantic-children="0,1" data-semantic- data-semantic-owns="0 1" data-semantic-role="unknown" data-semantic-speech="upper H f upper O 2" data-semantic-type="subscript"><mjx-mi data-semantic-font="normal" data-semantic- data-semantic-parent="2" data-semantic-role="unknown" data-semantic-type="identifier"><mjx-c noic="true" style="padding-top: 0.713em;">H</mjx-c><mjx-c noic="true" style="padding-top: 0.713em;">f</mjx-c><mjx-c style="padding-top: 0.713em;">O</mjx-c></mjx-mi><mjx-script style="vertical-align: -0.15em;"><mjx-mn data-semantic-annotation="clearspeak:simple" data-semantic-font="normal" data-semantic- data-semantic-parent="2" data-sema
机器学习力场的进步为分子动力学（MD）模拟开辟了新的途径，可以模拟那些因ab initio MD过于耗费资源而无法进行的化合物，以及那些经典力场无法充分模拟的现象。在此，我们描述了一种神经网络力场，其参数化的目的是重现 HfO2 的 r2SCAN 势能图。基于等温-等压（𝑁𝑃𝑇）集合的自动可微分实现，以及灵活的单元波动，我们研究了 HfO2 的相空间。我们发现晶格常数和 X 射线衍射实验数据具有极佳的预测能力。在 2000 K 左右的温度下，可以清楚地看到单斜相的转变，这与现有的实验数据和以前的计算结果一致。晶格常数的另一个突然变化发生在 3000 K 左右。虽然由此产生的晶格常数更接近立方体，但它们表现出很小的四方畸变，而且体积没有相关变化。我们的研究表明，这种高温结构与现有的高温衍射数据一致。
{"title":"Neural network enabled molecular dynamics study ofHfO2phase transitions","authors":"Sebastian Bichelmaier, Jesús Carrete, Georg K. H. Madsen","doi":"10.1103/physrevb.110.174105","DOIUrl":"https://doi.org/10.1103/physrevb.110.174105","url":null,"abstract":"The advances of machine-learned force fields have opened up molecular dynamics (MD) simulations for compounds for which <i>ab initio</i> MD is too resource intensive and phenomena for which classical force fields are insufficient. Here we describe a neural-network force field parametrized to reproduce the <mjx-container ctxtmenu_counter=\"23\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" overflow=\"linebreak\" role=\"tree\" sre-explorer- style=\"font-size: 100.7%;\" tabindex=\"0\"><mjx-math data-semantic-structure=\"(5 (2 0 1) 4 3)\"><mjx-mrow data-semantic-annotation=\"clearspeak:unit\" data-semantic-children=\"2,3\" data-semantic-content=\"4\" data-semantic- data-semantic-owns=\"2 4 3\" data-semantic-role=\"implicit\" data-semantic-speech=\"normal r squared upper S upper C upper A upper N\" data-semantic-type=\"infixop\"><mjx-msup data-semantic-children=\"0,1\" data-semantic- data-semantic-owns=\"0 1\" data-semantic-parent=\"5\" data-semantic-role=\"latinletter\" data-semantic-type=\"superscript\"><mjx-mrow><mjx-mi data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"2\" data-semantic-role=\"latinletter\" data-semantic-type=\"identifier\"><mjx-c>r</mjx-c></mjx-mi></mjx-mrow><mjx-script style=\"vertical-align: 0.363em;\"><mjx-mn data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"2\" data-semantic-role=\"integer\" data-semantic-type=\"number\" size=\"s\"><mjx-c>2</mjx-c></mjx-mn></mjx-script></mjx-msup><mjx-mo data-semantic-added=\"true\" data-semantic- data-semantic-operator=\"infixop,\" data-semantic-parent=\"5\" data-semantic-role=\"multiplication\" data-semantic-type=\"operator\"><mjx-c></mjx-c></mjx-mo><mjx-mi data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"5\" data-semantic-role=\"unknown\" data-semantic-type=\"identifier\" space=\"2\"><mjx-c noic=\"true\" style=\"padding-top: 0.669em;\">S</mjx-c><mjx-c noic=\"true\" style=\"padding-top: 0.669em;\">C</mjx-c><mjx-c noic=\"true\" style=\"padding-top: 0.669em;\">A</mjx-c><mjx-c style=\"padding-top: 0.669em;\">N</mjx-c></mjx-mi></mjx-mrow></mjx-math></mjx-container> potential energy landscape of <mjx-container ctxtmenu_counter=\"24\" ctxtmenu_oldtabindex=\"1\" jax=\"CHTML\" overflow=\"linebreak\" role=\"tree\" sre-explorer- style=\"font-size: 100.7%;\" tabindex=\"0\"><mjx-math data-semantic-structure=\"(2 0 1)\"><mjx-msub data-semantic-children=\"0,1\" data-semantic- data-semantic-owns=\"0 1\" data-semantic-role=\"unknown\" data-semantic-speech=\"upper H f upper O 2\" data-semantic-type=\"subscript\"><mjx-mi data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"2\" data-semantic-role=\"unknown\" data-semantic-type=\"identifier\"><mjx-c noic=\"true\" style=\"padding-top: 0.713em;\">H</mjx-c><mjx-c noic=\"true\" style=\"padding-top: 0.713em;\">f</mjx-c><mjx-c style=\"padding-top: 0.713em;\">O</mjx-c></mjx-mi><mjx-script style=\"vertical-align: -0.15em;\"><mjx-mn data-semantic-annotation=\"clearspeak:simple\" data-semantic-font=\"normal\" data-semantic- data-semantic-parent=\"2\" data-sema","PeriodicalId":20082,"journal":{"name":"Physical Review B","volume":"70 1","pages":""},"PeriodicalIF":3.7,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142597335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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