Correlation-driven threefold topological phase transition in monolayer OsBr_(2)  

作　　者：San-Dong Guo Yu-Ling Tao Wen-Qi Mu Bang-Gui Liu 

机构地区：[1]School of Electronic Engineering,Xi’an University of Posts and Telecommunications,Xi’an 710121,China [2]Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China [3]School of Physical Sciences,University of Chinese Academy of Sciences,Beijing 100190,China

出　　处：《Frontiers of physics》2023年第3期121-130,共10页物理学前沿（英文版）

基　　金：supported by the Natural Science Basis Research Plan in Shaanxi Province of China(No.2021JM-456);Graduate Innovation Fund Project in Xi’an University of Posts and Telecommunications(No.CXJJDL2021001);the National Natural Science Foundation of China(Grant No.11974393);the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB33020100).

摘　　要：Spin–orbit coupling(SOC)combined with electronic correlation can induce topological phase transition,producing novel electronic states.Here,we investigate the impact of SOC combined with correlation effects on physical properties of monolayer OsBr_(2),based on first-principles calculations with generalized gradient approximation plus U(GGA+U)approach.With intrinsic out-of-plane magnetic anisotropy,OsBr_(2)undergoes threefold topological phase transition with increasing U,and valleypolarized quantum anomalous Hall insulator(VQAHI)to half-valley-metal dxy dx2−y2 dz2¯6m2(HVM)to ferrovalley insulator(FVI)to HVM to VQAHI to HVM to FVI transitions can be induced.These topological phase transitions are connected with sign-reversible Berry curvature and band inversion between/and orbitals.Due to symmetry,piezoelectric polarization of OsBr_(2)is confined along the in-plane armchair direction,and only one d11 is independent.For a given material,the correlation strength should be fixed,and OsBr_(2)may be a piezoelectric VQAHI(PVQAHI),piezoelectric HVM(PHVM)or piezoelectric FVI(PFVI).The valley polarization can be flipped by reversing the magnetization of Os atoms,and the ferrovalley(FV)and nontrivial topological properties will be suppressed by manipulating out-of-plane magnetization to in-plane one.In considered reasonable U range,the estimated Curie temperatures all are higher than room temperature.Our findings provide a comprehensive understanding on possible electronic states of OsBr_(2),and confirm that strong SOC combined with electronic correlation can induce multiple quantum phase transition.

关 键 词：CORRELATION SOC phase transition PIEZOELECTRICITY 

分 类 号：O43[机械工程—光学工程]