单层Janus材料GaInSe2的电子结构第一原理计算

First-Principles Investigation of GaInSe2 Monolayer as a Janus Material

按照第一原理赝势平面波方法研究具有稳定间接带隙的单层Janus二维半导体GaInSe2的电子结构,探讨构建Janus结构的单层GaSe和InSe与GaInSe2的结构和电子性质之间的内禀关系。原子结构和声子色散谱的计算结果证明单层GaInSe2与GaSe和InSe有着相似的六边形几何构型,具有动态稳定的Janus结构。电子能带结构表明GaInSe2与其二元类似物GaSe和InSe都是间接带隙半导体,GaSe和InSe之间的应变和功函数决定了单层GaInSe2电子结构的基本特征。当原子层平面方向上的应变小于临界值时,单层GaInSe2可转化为直接带隙半导体。因此,在应变小于临界应变的力学条件下,单层GaInSe2可用作二维或表面光电材料。此外,通过调节层平面方向上的应变,可以有效地控制GaInSe2能带的带边特性和带隙宽度,这对于场效应晶体管的潜在应用具有重要意义。

The stable GaInSe2 monolayer as a Janus structure with an indirect band-gap was investigated via first-principles electronic structure calculations.The intrinsic correlation between GaInSe2 monolayer and its binary analogues(Ga Se and In Se monolayers)was investigated in terms of atomic structure and electronic property.The calculation results of atomic structure and phonon frequency dispersion indicate that GaInSe2 monolayer has a dynamically stable Janus structure with the similar hexagonal geometry as GaSe and InSe monolayers.The electronic band structures show that GaInSe2 monolayer and its binary analogues are all indirect band-gap semiconductors.It is noted from the strained Janus model that work functions and coherent strains of GaSe and InSe constituents essentially determine the electronic structure of GaInSe2 monolayer.GaInSe2 monolayer can be converted into direct band-gap semiconductor when the strain in atomic plane is decreased less than a critical value.Therefore,GaInSe2 monolayer can be applied to 2-dimensional or surface photoelectric materials under the mechanical conditions below the critical strain.Further,the band-edge character and band-gap width can be effectively controlled by modifying the strains in atomic plane of GaInSe2 monolayer,which is of great significance for the potential application in field effect nanotransistors.