外电场下单层InSe电子结构的第一性原理计算

First-Principles calculations of the electronic structure of monolayer InSe under external electric field

由于具有大的塞贝克系数和电导率,单层InSe具有优异的热电性能。采用第一性原理计算方法系统地研究了外电场作用下单层InSe的结构、电子结构和电荷转移。研究结果表明,当电场强度在0~0.6 V/?时,费米能级附近的导带和价带对外电场的作用不敏感,且带隙几乎不随外电场变化。主要是因为施加外电场后,上、下Se-In原子层周围的自由电子发生了转移,使得单层InSe对外电场有屏蔽作用;在屏蔽效应下,单层InSe的结构及其内部化学键受到外电场的影响较小,使得单层InSe的能带对外电场作用不敏感。本研究可为二维材料电子结构和物性的外电场调控机制提供一定的理论参考。

Monolayer InSe has excellent thermoelectric properties due to its large Seebeck coefficient and electrical conductivity.Using first-principles calculations,the structure,electronic structure and charge transfer of monolayer InSe under the external electric field were systematically studied.The results show that when the electric field strength is in the range of 0-0.6 V/Å,the conduction band and the valence band near the Fermi level are insensitive to the external electric field,and the band gap hardly changes with the external electric field.This is mainly due to the transfer of free electrons around the upper and lower Se-In atomic layers after the application of an external electric field,which makes the monolayer InSe shield the external electric field.Under the shielding effect,the structure of the monolayer InSe and its internal chemical bonds are less affected by the external electric field,which makes the energy band of the monolayer InSe insensitive to the external electric field.This study can provide a theoretical reference for the regulation mechanism of external electric field on the electronic structure and physical properties of two-dimensional materials.