论文标题
垂直电场下单层和双层Janus HFSSE的电气和自旋特性
The Electrical and Spin Properties of Monolayer and Bilayer Janus HfSSe under Vertical Electrical Field
论文作者
论文摘要
在本文中，研究了在垂直电场存在下单层和双层HFSSE的电和自旋特性。密度功能理论用于研究其特性。考虑了15种不同的双层HFSSE堆叠顺序。单层和双层表现出间接的带隙，而双层的带隙可以通过电场有效控制。虽然双层的带隙在大型电场上关闭，并且会发生到金属过渡的半导体，但正常电场对单层HFSSE带隙的影响非常弱。自旋轨道耦合会导致在单声和双层结构的导带中的价带中的带和Rashba自旋分裂。在双层的价带中分裂的带小于单层，但是，垂直电场增加了双层中的频带分裂。没有镜子对称性的堆叠配置表现出Rashba自旋分裂，并通过电场增强。
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 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.
