Ghobadi Nayereh, Touski Shoeib Babaee
Department of Electrical Engineering, University of Zanjan, Zanjan, Iran.
Department of Electrical Engineering, Hamedan University of Technology, Hamedan, Iran.
J Phys Condens Matter. 2021 Feb 24;33(8):085502. doi: 10.1088/1361-648X/abcb12.
In this paper, the electrical and spin properties of mono- and bilayer HfSSe in the presence of a vertical electric field are studied. The density functional theory is used to investigate their properties. Fifteen different stacking orders of bilayer HfSSe are considered. The mono- and bilayer demonstrate an indirect bandgap, whereas the bandgap of bilayer can be effectively controlled by the electric field. While the bandgap of bilayer closes at large electric fields and a semiconductor to metal transition occurs, the effect of a normal electric field on the bandgap of the monolayer HfSSe is quite weak. Spin-orbit coupling causes band splitting in the valence band and Rashba spin splitting in the conduction band of both mono- and bilayer structures. The band splitting in the valence band of the bilayer is smaller than a monolayer, however, the vertical electric field increases the band splitting in bilayer one. The stacking configurations without mirror symmetry exhibit Rashba spin splitting which is enhanced with the electric field.
本文研究了垂直电场作用下单层和双层HfSSe的电学和自旋性质。采用密度泛函理论来研究它们的性质。考虑了双层HfSSe的十五种不同堆叠顺序。单层和双层均表现出间接带隙，而双层的带隙可通过电场有效控制。虽然双层的带隙在大电场下关闭并发生半导体到金属的转变，但垂直电场对单层HfSSe带隙的影响相当微弱。自旋轨道耦合导致单层和双层结构的价带中出现能带分裂以及导带中出现Rashba自旋分裂。双层价带中的能带分裂小于单层，然而，垂直电场增加了双层中的能带分裂。没有镜面对称性的堆叠构型表现出Rashba自旋分裂，且其随电场增强。
