Coupled structural and electronic phase transitions underlie the multifunctional properties of strongly-correlated materials. For example, colossal magnetoresistance1,2 in manganites involves phase transition from paramagnetic insulator to ferromagnetic metal linked to a structural Jahn-Teller distortion3. Vanadium dioxide (VO2) likewise exhibits an insulator-to-metal transition (IMT) at ~67oC with abrupt changes in transport and optical properties and coupled to a structural phase transition (SPT) from monoclinic to tetragonal4. The IMT and SPT hystereses are signatures of first-order phase transition tracking the nucleation to stabilization of a new phase. Here we have for the first time measured independently the IMT and SPT hystereses in epitaxial VO2 films, and shown that the hystereses are not congruent. From the measured volume fractions of the two phases in the region of strong correlation, we have computed the evolving dielectric function under an effective-medium approximation. But the computed dielectric functions could not reproduce the measured IMT, implying that there is a strongly correlated metallic phase that is not in the stable rutile structure, consistent with Qazilbash et al5. Search for a corresponding macroscopic structural intermediate also yielded negative result.
Thermally quenched metastability in metal-insulator transitions via elemental substitution
The University of Tokyo（东京大学）；National Institute of Advanced Industrial Science and Technology（产业技术综合研究所）；Graduate School of Engineering and Science, Shibaura Institute of Technology（芝浦工业大学研究生院理工学研究科）；RIKEN Center for Emergent Matter Science（理化学研究所新兴物质科学研究中心）；University of Tsukuba（筑波大学）；Institute of Science Tokyo（东京科学大学）；National Institute for Materials Science（国立材料研究所）
Unveiling the critical role of interfacial strain in adjusting electronic phase transitions in correlated vanadium dioxide
Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education & School of Materials Science and Engineering, Shanxi Normal University（山西师范大学 磁性分子与磁信息材料教育部重点实验室 & 材料科学与工程学院）；Research Institute of Materials Science, Shanxi Key Laboratory of Advanced Magnetic Materials and Devices, Shanxi Normal University（山西师范大学 材料科学研究所 & 山西省先进磁性材料与器件重点实验室）
Thermally-driven reorientation of the Néel vector in altermagnetic MnTe
PSI Center for Neutron and Muon Sciences（瑞士保罗谢勒研究所中子与μ子科学中心）；Faculty of Mathematics and Physics, Charles University（布拉格查理大学数学与物理学院）；Institute of Physics, Czech Academy of Sciences（捷克科学院物理研究所）；Department of Condensed Matter Physics, Faculty of Science, Masaryk University（布尔诺马萨里克大学理学院凝聚态物理系）；School of Physics and Astronomy, University of Nottingham（诺丁汉大学物理与天文学学院）；PSI Center for Photon Science（瑞士保罗谢勒研究所光子科学中心）；Institut de Physique, École Polytechnique Fédérale de Lausanne（洛桑联邦理工学院物理研究所）
Finite-Temperature Thermally-Assisted-Occupation Density Functional Theory, Ab Initio Molecular Dynamics, and Quantum Mechanics/Molecular Mechanics Methods
National Taiwan University（台湾大学）；Department of Physics, National Taiwan University（台湾大学物理系）；Center for Theoretical Physics and Center for Quantum Science and Engineering, National Taiwan University（台湾大学理论物理中心与量子科学与工程中心）；Physics Division, National Center for Theoretical Sciences（国家理论科学中心物理组）
Investigation of the Electronic Structure and Spin-State Crossover in LaCoO3 Using Photoemission Spectroscopy
Institute of Physics（印度物理研究所）；Homi Bhabha National Institute（霍米·巴巴国立研究所）；Institute for Solid State Physics, The University of Tokyo（东京大学固体物理研究所）；Deutsches Elektronen-Synchrotron DESY（德国电子同步加速器中心）
