层状MnSb_(2)Te_(4)/Sb_(2)Te_(3)异质结的拓扑性质

Topological properties of layered MnSb_(2)Te_(4)/Sb_(2)Te_(3)heterojunctions

作为一种典型的拓扑态,量子反常霍尔效应引起了人们的广泛关注.本文通过第一性原理计算研究了不同层间距时的MnSb_(2)Te_(4)/Sb_(2)Te_(3)范德瓦尔斯异质结的电子结构及拓扑性质.结果发现MnSb_(2)Te_(4)/Sb_(2)Te_(3)体系表现为拓扑平庸相.而将MnSb_(2)Te_(4)中Te与Sb原子层距离调节为2.3A时,体系在自旋轨道耦合作用下出现了能带反转,实现了从拓扑平庸相到拓扑非平庸相的转变.能带结构和拓扑性质计算表明,体系陈数为1,且存在一个14.5meV的拓扑非平庸带隙、一维手性边缘态和量子化的霍尔电导,可实现零场下非零陈数的量子反常霍尔效应.我们的工作为其他磁性范德瓦尔斯体系实现量子反常霍尔效应的研究提供了参考.

As a typical topological state,quantum anomalous Hall effect has attracted wide attention.In this paper,the electronic structure and topological properties of MnSb_(2)Te_(4)/Sb_(2)Te_(3)van der Waals heterojunction at different interlayer spacing are studied by first-principles calculation.It is found that MnSb_(2)Te_(4)/Sb_(2)Te_(3)system behaves as a topologically trivial phase.By adjusting the distance between Te and Sb atomic layer in MnSb_(2)Te_(4)to 2.3Å,band inversion occurs in the system under the action of Spin-orbit coupling,and the transformation from topologically trivial phase to topologically nontrivial phase is realized.The calculation of band structure and topological properties shows that the Chern number of the system is 1,Moreover,there exists a 14.5 meV topological nontrivial band gap,a chiral edge state and quantized Hall conductance,which can realize the quantum anomalous Hall effect of nonzero Chern number in zero field.Our work provides a reference for other magnetic van der Waals systems to realize quantum anomalous Hall effects.