Antiferromagnetic second-order topological insulator with fractional mass-kink  

作　　者：Haimen Mu Gan Zhao Huimin Zhang Zhengfei Wang 

机构地区：[1]Hefei National Laboratory for Physical Sciences at the Microscale,CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics,Department of Physics,University of Science and Technology of China,Hefei,Anhui,230026,China [2]Key Laboratory of Material Modification by Laser,Ion and Electron Beams,Dalian University of Technology,Ministry of Education,Dalian,116024,China

出　　处：《npj Computational Materials》2022年第1期788-794,共7页计算材料学（英文）

基　　金：This work was supported by NSFC(Grant No.12174369,11774325,and 21603210);National Key Research and Development Program of China(Grant No.2017YFA0204904);Fundamental Research Funds for the Central Universities.

摘　　要：Generally,the topological corner state in two-dimensional(2D)second-order topological insulator(SOTI)is equivalent to the well-known domain wall state,which is originated from the mass-inversion between two adjacent edges with phase shift ofπ.In this work,go beyond this conventional physical picture,we report a fractional mass-kink induced 2D SOTI in monolayer FeSe with canted checkerboard antiferromagnetic(AFM)order by analytic model and first-principles calculations.The canted spin associated in-plane Zeeman field can gap out the quantum spin Hall edge state of FeSe,forming a fractional mass-kink with phase shift ofπ/2 at the rectangular corner,and generating an in-gap topological corner state with fractional charge of e/4.Moreover,the topological corner state is robust to a finite perturbation,existing in both naturally and non-naturally cleaved corners,regardless of the edge orientation.Our results not only demonstrate a material system to realize the unique 2D AFM SOTI,but also pave a way to design the higher-order topological states from fractional mass-kink with arbitrary phase shift.

关 键 词：TOPOLOGICAL FRACTIONAL INSULATOR 

分 类 号：O17[理学—数学]