Physical Review X最新文献

{"title":"Damaging Intermolecular Relaxation Processes Initiated by Heavy-Ion Irradiation of Hydrated Biomolecules","authors":"Yue Gao, Anna D. Skitnevskaya, Enliang Wang, Hang Yuan, Xueguang Ren, Hong Lin, Zhenyu Yan, Shaofeng Zhang, Shaofei Gu, Bo Yang, Feng Fang, Shuncheng Yan, Dalong Guo, Xiaolong Zhu, Dongmei Zhao, Caojie Shao, Zhongkui Huang, Xiaorui Xue, Xintai Hao, Jiaqi Zhou, Tongmin Zhang, Jinyu Li, Xinliang Yan, Meng Wang, Lijun Mao, Dayu Yin, Meitang Tang, Youjin Yuan, Jiancheng Yang, Alexander B. Trofimov, Lorenz S. Cederbaum, Alexander I. Kuleff, Xinwen Ma, Shenyue Xu","doi":"10.1103/physrevx.15.011053","DOIUrl":"https://doi.org/10.1103/physrevx.15.011053","url":null,"abstract":"Intermolecular Coulombic decay (ICD) is considered a general phenomenon that plays a key role in many fundamental and applied fields related to biological environments. In many cases, however, the mechanisms and efficiency of ICD have yet to be uncovered. A prominent example is heavy-ion cancer therapy. Here, we report the first detection of a damaging intermolecular relaxation cascade initiated by heavy-ion bombardment of hydrated pyrimidine clusters. The process can significantly contribute to the high biological effectiveness of heavy-ion irradiation and thus might play an essential role in many radiotherapy techniques. Inner-valence ionization of the cluster initiates ICD and triggers proton transfer between water molecules, producing destructive low-energy electrons, HO</a:mi></a:mrow>•</a:mo></a:mrow></a:msup></a:mrow></a:math> radicals, and hydrated protons. Notably, the efficiency of ICD was found to increase dramatically with the number of water molecules, making ICD the dominant decay mechanism after inner-valence ionization. These findings indicate that the biological damage, caused by ICD in aqueous environments, is much more severe than was previously recognized. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"52 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143599004","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}

{"title":"Electric-Field Switchable Chirality in Rhombohedral Graphene Chern Insulators Stabilized by Tungsten Diselenide","authors":"Jing Ding, Hanxiao Xiang, Jiannan Hua, Wenqiang Zhou, Naitian Liu, Le Zhang, Na Xin, Bing Wu, Kenji Watanabe, Takashi Taniguchi, Zdeněk Sofer, Wei Zhu, Shuigang Xu","doi":"10.1103/physrevx.15.011052","DOIUrl":"https://doi.org/10.1103/physrevx.15.011052","url":null,"abstract":"Chern insulators host topologically protected chiral edge currents with quantized conductance characterized by their Chern number. Switching the chirality of a Chern insulator, namely, the direction of the edge current, is highly challenging due to topologically forbidden backscattering but is of considerable importance for the design of topological devices. Nevertheless, this can be achieved by reversing the sign of the Chern number. Here, we report electrically switchable chirality in rhombohedral multilayer graphene-based Chern insulators through a topological phase transition. By introducing moiré superlattices in rhombohedral heptalayer graphene, we observe a cascade of topological phase transitions at quarter electron filling of a moiré band with the Chern number tunable from −</a:mo>1</a:mn></a:mrow></a:math>, 1, to 2. Furthermore, integrating monolayer tungsten diselenide at the moiréless interface of rhombohedral decalayer graphene and hexagonal boron nitride superlattices stabilizes the Chern insulators, enabling quantized anomalous Hall resistance of <c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><c:mrow><c:mi>h</c:mi><c:mo stretchy=\"false\">/</c:mo><c:mn>2</c:mn><c:msup><c:mi>e</c:mi><c:mn>2</c:mn></c:msup></c:mrow></c:math>. Remarkably, the Chern number can be electrically switched using displacement fields, leading to a topological phase transition from <f:math xmlns:f=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><f:mrow><f:mo>−</f:mo><f:mn>1</f:mn></f:mrow></f:math> to 2. Our work establishes rhombohedral multilayer graphene moiré superlattices as a versatile platform for topological engineering, with switchable chirality offering significant promise for integrating chiral edge currents into topological electronic circuits. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"31 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143589807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}

{"title":"Exploring Atom-Ion Feshbach Resonances below the s -Wave Limit","authors":"Fabian Thielemann, Joachim Siemund, Daniel von Schoenfeld, Wei Wu, Pascal Weckesser, Krzysztof Jachymski, Thomas Walker, Tobias Schaetz","doi":"10.1103/physrevx.15.011051","DOIUrl":"https://doi.org/10.1103/physrevx.15.011051","url":null,"abstract":"Hybrid systems of single, trapped ions embedded in quantum gases are a promising platform for quantum simulations and the study of long-range interactions in the ultracold regime. Feshbach resonances allow for experimental control over the character and strength of the atom-ion interaction. However, the complexity of atom-ion Feshbach spectra, e.g., due to second-order spin-orbit coupling, requires a detailed experimental understanding of the resonance properties—such as the contributing open-channel partial waves. In this work, we immerse a single barium (Ba</a:mi></a:mrow>+</a:mo></a:mrow></a:msup></a:mrow></a:math>) ion in a bath of lithium (Li) atoms spin polarized in their hyperfine ground state to investigate the collision energy dependence of magnetically tunable atom-ion Feshbach resonances. We demonstrate fine control over the kinetic energy of the <c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><c:mrow><c:msup><c:mrow><c:mi>Ba</c:mi></c:mrow><c:mrow><c:mo>+</c:mo></c:mrow></c:msup></c:mrow></c:math> ion and employ it to explore three-body recombination in the transition from the many- to the few-partial wave regime, marked by a sudden increase of resonant loss. In a dense spectrum—with on average 0.58(1) resonances per Gauss—we select a narrow, isolated feature and characterize it as an <e:math xmlns:e=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><e:mi>s</e:mi></e:math>-wave resonance. We introduce a quantum recombination model that allows us to distinguish it from higher-partial-wave resonances. Furthermore, in a magnetic field range with no significant loss at the lowest collision energies, we identify a higher-partial-wave resonance that appears and peaks only when we increase the energy to around the <g:math xmlns:g=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><g:mi>s</g:mi></g:math>-wave limit. Our results demonstrate that hybrid atom-ion traps can reach collision energies well in the ultracold regime and that the ion’s kinetic energy can be employed to tune the collisional complex to resonance, paving the way for fast control over the interaction in settings where magnetic field variations are detrimental to coherence. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"584 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143575211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}

{"title":"Confined Trions and Mott-Wigner States in a Purely Electrostatic Moiré Potential","authors":"Natasha Kiper, Haydn S. Adlong, Arthur Christianen, Martin Kroner, Kenji Watanabe, Takashi Taniguchi, Atac İmamoğlu","doi":"10.1103/physrevx.15.011049","DOIUrl":"https://doi.org/10.1103/physrevx.15.011049","url":null,"abstract":"Moiré heterostructures consisting of transition metal dichalcogenide (TMD) heterobilayers and homobilayers have emerged as a promising material platform to study correlated electronic states. Optical signatures of strong correlations in the form of Mott-Wigner states and fractional Chern insulators have already been observed in TMD monolayers and their twisted bilayers. In this work, we use a moiré substrate containing a twisted hexagonal boron nitride (h</a:mi></a:mrow></a:math>-BN) interface to externally generate a superlattice potential for the TMD layer: The periodic structure of ferroelectric domains in <c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><c:mrow><c:mi>h</c:mi></c:mrow></c:math>-BN creates a purely electrostatic potential for charge carriers. We find direct evidence for the induced moiré potential in the emergence of new excitonic resonances at integer fillings and our observation of an enhancement of the trion binding energy by <e:math xmlns:e=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><e:mrow><e:mo>≃</e:mo><e:mn>3</e:mn><e:mtext> </e:mtext><e:mtext> </e:mtext><e:mi>meV</e:mi></e:mrow></e:math>. A theoretical model for exciton-electron interactions allows us to directly determine the moiré potential modulation of <g:math xmlns:g=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><g:mn>30</g:mn><g:mo>±</g:mo><g:mn>5</g:mn><g:mtext> </g:mtext><g:mtext> </g:mtext><g:mi>meV</g:mi></g:math> from the measured trion binding energy shift. We obtain direct evidence for charge order linked to electronic Mott-Wigner states at filling factors <i:math xmlns:i=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><i:mi>ν</i:mi><i:mo>=</i:mo><i:mn>1</i:mn><i:mo>/</i:mo><i:mn>3</i:mn></i:math> and <k:math xmlns:k=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><k:mi>ν</k:mi><k:mo>=</k:mo><k:mn>2</k:mn><k:mo>/</k:mo><k:mn>3</k:mn></k:math> through the associated exciton umklapp resonances. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"67 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143569702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}

{"title":"Optical Absorption Spectroscopy Probes Water Wire and Its Ordering in a Hydrogen-Bond Network","authors":"Fujie Tang, Diana Y. Qiu, Xifan Wu","doi":"10.1103/physrevx.15.011048","DOIUrl":"https://doi.org/10.1103/physrevx.15.011048","url":null,"abstract":"Water wires, quasi-one-dimensional chains composed of hydrogen-bonded (H-bonded) water molecules, play a fundamental role in numerous chemical, physical, and physiological processes. Yet direct experimental detection of water wires has been elusive so far. Based on advanced many-body theory that includes electron-hole interactions, we report that optical absorption spectroscopy can serve as a sensitive probe of water wires and their ordering. In both liquid and solid water, the main peak of the spectrum is discovered to be a charge-transfer exciton. In water, the charge-transfer exciton is strongly coupled to the H-bonding environment where the exciton is excited between H-bonded water molecules with a large spectral intensity. In regular ice, the spectral weight of the charge-transfer exciton is enhanced by a collective excitation occurring on proton-ordered water wires, whose spectral intensity scales with the ordering length of water wire. The spectral intensity and excitonic interaction strength reaches its maximum in ice XI, where the long-range ordering length yields the most pronounced spectral signal. Our findings suggest that water wires, which widely exist in important physiological and biological systems and other phases of ice, can be directly probed by this approach. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"37 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143570290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}

{"title":"Spin Seebeck Effect as a Probe for Majorana Fermions in Kitaev Spin Liquids","authors":"Yasuyuki Kato, Joji Nasu, Masahiro Sato, Tsuyoshi Okubo, Takahiro Misawa, Yukitoshi Motome","doi":"10.1103/physrevx.15.011050","DOIUrl":"https://doi.org/10.1103/physrevx.15.011050","url":null,"abstract":"Quantum entanglement in strongly correlated electron systems often leads to exotic elementary excitations. Quantum spin liquids provide a paradigmatic example, where the elementary excitations are described by fractional quasiparticles such as spinons. However, such fractional quasiparticles behave differently from electrons, making their experimental identification challenging. Here, we theoretically investigate the spin Seebeck effect, which is a thermoelectric response via a spin current, as an efficient probe of the fractional quasiparticles in quantum spin liquids, focusing on the Kitaev honeycomb model. By comprehensive studies using real-time dynamics, perturbation theory, and linear spin-wave theory based on the tunnel spin-current theory, we find that the spin current is induced by thermal gradient in the Kitaev spin liquid via the low-energy fractional Majorana excitations. This identification underscores the ability of Majorana fermions to carry spin current, despite lacking spin angular momentum. Furthermore, we find that the induced spin current changes its sign depending on the sign of the Kitaev interaction, indicating that the Majorana fermions contribute to the spin current with (up-) down-spin-like nature when the exchange coupling is (anti)ferromagnetic. Thus, in contrast to the negative spin current already found in a one-dimensional quantum spin liquid, our calculation reveals that the spin Seebeck effect can exhibit either positive or negative signals, contingent upon the nature of fractional excitations in the quantum spin liquids. We also clarify contrasting field-angle dependence between the Kitaev spin liquid in the low-field limit and the high-field ferromagnetic state, which is useful for the experimental identification. Our finding suggests that the spin Seebeck effect could be used not only to detect fractional quasiparticles emerging in quantum spin liquids but also to generate and control them. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"85 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143569740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}

{"title":"Spin- 1/2 Kagome Heisenberg Antiferromagnet: Machine Learning Discovery of the Spinon Pair-Density-Wave Ground State","authors":"Tanja Đurić, Jia Hui Chung, Bo Yang, Pinaki Sengupta","doi":"10.1103/physrevx.15.011047","DOIUrl":"https://doi.org/10.1103/physrevx.15.011047","url":null,"abstract":"The spin-1</a:mn>/</a:mo>2</a:mn></a:mrow></a:math> kagome antiferromagnet (AFM) is one of the most studied models in frustrated magnetism since it is a promising candidate to host exotic spin-liquid states. However, despite numerous studies using both analytical and numerical approaches, the nature of the ground state and low-energy excitations in this system remains elusive. This challenge is related to the difficulty in determining the spin gap in various calculations. We present the results of our investigation of the kagome AFM using the recently developed group equivariant convolutional neural networks—a novel machine learning technique for studying strongly frustrated models. This approach, combined with variational Monte Carlo method, introduces significant improvement of the achievable results’ accuracy for frustrated spin systems in comparison with approaches based on other neural-network architectures. Contrary to the results obtained previously with various methods, which predicted <c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><c:mrow><c:msub><c:mrow><c:mi mathvariant=\"double-struck\">Z</c:mi></c:mrow><c:mrow><c:mn>2</c:mn></c:mrow></c:msub></c:mrow></c:math> or <f:math xmlns:f=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><f:mi>U</f:mi><f:mo stretchy=\"false\">(</f:mo><f:mn>1</f:mn><f:mo stretchy=\"false\">)</f:mo></f:math> Dirac spin-liquid states, our results strongly indicate that the ground state of the kagome lattice antiferromagnet is a spinon pair density wave that does not break time-reversal symmetry or any of the lattice symmetries. The state appears due to the spinon Cooper pairing instability close to two Dirac points in the spinon energy spectrum, and it resembles the pair density wave state studied previously in the context of underdoped cuprate superconductors in connection with the pseudogap phase. This state has significantly lower energy than the lowest-energy states found by the <j:math xmlns:j=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><j:mi>S</j:mi><j:mi>U</j:mi><j:mo stretchy=\"false\">(</j:mo><j:mn>2</j:mn><j:mo stretchy=\"false\">)</j:mo></j:math> symmetric density matrix renormalization group calculations and other methods. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"52 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143538676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}

{"title":"Impact of Andreev Bound States within the Leads of a Quantum Dot Josephson Junction","authors":"Alberto Bordin, Florian J. Bennebroek Evertsz’, Gorm O. Steffensen, Tom Dvir, Grzegorz P. Mazur, David van Driel, Nick van Loo, Jan Cornelis Wolff, Erik P. A. M. Bakkers, Alfredo Levy Yeyati, Leo P. Kouwenhoven","doi":"10.1103/physrevx.15.011046","DOIUrl":"https://doi.org/10.1103/physrevx.15.011046","url":null,"abstract":"Detection and control of Andreev bound states (ABSs) localized at semiconductor-superconductor interfaces are essential for their use in quantum applications. Here we investigate the impact of ABSs on the supercurrent through a Josephson junction containing a quantum dot (QD). Additional normal-metal tunneling probes on both sides of the junction unveil the ABSs residing at the semiconductor-superconductor interfaces. Such knowledge provides an ingredient missing in previous studies, improving the connection between theory and experimental data. By varying the ABS energies using electrostatic gates, we show control of the switching current, with the ability to alter it by more than an order of magnitude. Finally, the large degree of ABS tunability allows us to realize a three-site Andreev molecule in which the central QD is screened by both ABSs. This system is studied simultaneously using both supercurrent and spectroscopy. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"16 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143538678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}

{"title":"Chern Insulators at Integer and Fractional Filling in Moiré Pentalayer Graphene","authors":"Dacen Waters, Anna Okounkova, Ruiheng Su, Boran Zhou, Jiang Yao, Kenji Watanabe, Takashi Taniguchi, Xiaodong Xu, Ya-Hui Zhang, Joshua Folk, Matthew Yankowitz","doi":"10.1103/physrevx.15.011045","DOIUrl":"https://doi.org/10.1103/physrevx.15.011045","url":null,"abstract":"The advent of moiré platforms for engineered quantum matter has led to discoveries of integer and fractional quantum anomalous Hall effects, with predictions for correlation-driven topological states based on electron crystallization. Here, we report an array of trivial and topological insulators formed in a moiré lattice of rhomobohedral pentalayer graphene (R5G). At a doping of one electron per moiré unit cell (ν</a:mi>=</a:mo>1</a:mn></a:math>), we see a correlated insulator with a Chern number that can be tuned between <c:math xmlns:c=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><c:mi>C</c:mi><c:mo>=</c:mo><c:mn>0</c:mn></c:math> and <e:math xmlns:e=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><e:mo>+</e:mo><e:mn>1</e:mn></e:math> by an electric displacement field. This is accompanied by a series of additional Chern insulators with <g:math xmlns:g=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><g:mi>C</g:mi><g:mo>=</g:mo><g:mo>+</g:mo><g:mn>1</g:mn></g:math> originating from fractional fillings of the moiré lattice—<i:math xmlns:i=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><i:mi>ν</i:mi><i:mo>=</i:mo><i:mn>1</i:mn><i:mo>/</i:mo><i:mn>4</i:mn></i:math>, <k:math xmlns:k=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><k:mn>1</k:mn><k:mo>/</k:mo><k:mn>3</k:mn></k:math>, and <m:math xmlns:m=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><m:mn>2</m:mn><m:mo>/</m:mo><m:mn>3</m:mn></m:math>—associated with the formation of moiré-driven topological electronic crystals. At <o:math xmlns:o=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><o:mi>ν</o:mi><o:mo>=</o:mo><o:mn>2</o:mn><o:mo>/</o:mo><o:mn>3</o:mn></o:math> the system exhibits an integer quantum anomalous Hall effect at zero magnetic field, but further develops hints of an incipient <q:math xmlns:q=\"http://www.w3.org/1998/Math/MathML\" display=\"inline\"><q:mi>C</q:mi><q:mo>=</q:mo><q:mn>2</q:mn><q:mo>/</q:mo><q:mn>3</q:mn></q:math> fractional Chern insulator in a modest field. Our results establish moiré R5G as a fertile platform for studying the competition and potential intertwining of integer and fractional Chern insulators. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"32 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143517876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}

{"title":"Light-Induced Reorientation Transition in an Antiferromagnetic Semiconductor","authors":"Bryan T. Fichera, Baiqing Lv, Karna Morey, Zongqi Shen, Changmin Lee, Elizabeth Donoway, Alex Liebman-Peláez, Anshul Kogar, Takashi Kurumaji, Martin Rodriguez-Vega, Rodrigo Humberto Aguilera del Toro, Mikel Arruabarrena, Batyr Ilyas, Tianchuang Luo, Peter Müller, Aritz Leonardo, Andres Ayuela, Gregory A. Fiete, Joseph G. Checkelsky, Joseph Orenstein, Nuh Gedik","doi":"10.1103/physrevx.15.011044","DOIUrl":"https://doi.org/10.1103/physrevx.15.011044","url":null,"abstract":"Because of the lack of a net magnetic moment, antiferromagnets possess a unique robustness to external magnetic fields and are thus predicted to play an important role in future magnetic technologies. However, this robustness also makes them quite difficult to control, and the development of novel methods to manipulate these systems with external stimuli is a fundamental goal of antiferromagnetic spintronics. In this work, we report evidence for a metastable reorientation of the order parameter in an antiferromagnetic semiconductor triggered by an ultrafast quench of the equilibrium order via photoexcitation above the band gap. The metastable state forms less than 10 ps after the excitation pulse, and persists for longer than 150 ps before decaying to the ground state via thermal fluctuations. Importantly, this transition cannot be induced thermodynamically, and requires the system to be driven out of equilibrium. Broadly speaking, this phenomenology is ultimately the result of large magnetoelastic coupling in combination with a relatively low symmetry of the magnetic ground state. Since neither of these properties are particularly uncommon in magnetic materials, the observations presented here imply a generic path toward novel device technology enabled by ultrafast dynamics in antiferromagnets. <jats:supplementary-material> <jats:copyright-statement>Published by the American Physical Society</jats:copyright-statement> <jats:copyright-year>2025</jats:copyright-year> </jats:permissions> </jats:supplementary-material>","PeriodicalId":20161,"journal":{"name":"Physical Review X","volume":"15 1","pages":""},"PeriodicalIF":12.5,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143506838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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}