Janus monolayers Fe_(2)SSeX_(2)(X=Ga,In,and Tl):Robust nontrivial topology with high Chern number  

作　　者：Kang Jia Xiao-Jing Dong Pei-Ji Wang Chang-Wen Zhang 贾康;董晓晶;王培吉;张昌文(School of Physics and Technology,Institute of Spintronics,University of Jinan,Jinan 250022,China;School of Physics and Physical Engineering,Qufu Normal University,Qufu 273165,China)

机构地区：[1]School of Physics and Technology,Institute of Spintronics,University of Jinan,Jinan 250022,China [2]School of Physics and Physical Engineering,Qufu Normal University,Qufu 273165,China

出　　处：《Chinese Physics B》2024年第12期382-388,共7页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China(Grant Nos.52173283 and 62071200);Taishan Scholar Program of Shandong Province(Grant No.ts20190939);Independent Cultivation Program of Innovation Team of Jinan City(Grant No.2021GXRC043)。

摘　　要：High-performance quantum anomalous Hall(QAH)systems are crucial materials for exploring emerging quantum physics and magnetic topological phenomena.Inspired by layered FeSe materials with excellent superconducting properties,the Janus monolayers Fe_(2)SSeX_(2)(X=Ga,In and Tl)are built by the decoration of Ga,In and T1 atoms in monolayer Fe_(2)SSe.In first-principles calculations,Fe_(2)SSeX_(2)have stable structures and prefer ferromagnetic(FM)ordering,and can be considered as Weyl semimetals without spin-orbit coupling.For out-of-plane(OOP)magnetic anisotropy,large nontrivial gaps are opened and the Fe_(2)SSeX_(2)are predicted to be large-gap QAH insulators with a high Chern number C=2,proved by two chiral edge states and Berry curvature.When the magnetization is flipped,the two chiral edge states can be simultaneously changed and C=-2 can be obtained,revealing the fascinating behavior of chiral spin-edge state locking.It is found that the QAH properties of Fe_(2)SSeX_(2)are robust against strain.In particular,nontrivial topological quantum states can spontaneously appear for Fe_(2)SSeGa_(2)and Fe_(2)SSeIn_(2)because the orientations of the easy magnetic axis are adjusted from in-plane to OOP by the biaxial strain.Our studies provide excellent candidate systems to realize QAH properties with a high Chern number,and suggest more experimental explorations combining superconductivity and topology.

关 键 词：Weyl semimetal high Chern number chiral spin-edge state locking ROBUST 

分 类 号：O469[理学—凝聚态物理]