热电材料SnX(X=S,Se,Te)的电子结构和弹性性质的第一性原理研究

First-principles Study of Electronic and Elastic Properties of SnX(X=S,Se,Te)

采用基于密度泛函理论的第一性原理方法研究了热电材料SnX(X=S,Se,Te)的单层和块体结构的电子性质,并对块体结构SnX的弹性性质进行计算和分析,计算结果与文献中理论和实验结果相符。通过对能带和态密度的计算,发现单层和块体结构的SnX均为间接带隙半导体,带隙均随着X原子序数的增大而减小。根据计算得到的块体结构的弹性常数C_(ij)、体弹模量B和剪切模量G等值,发现SnX是力学稳定的,且它们都表现出脆性,并由弹性各向异性因子得到SnX具有弹性各向异性。

First-principles methods based on density functional theory are used to research the electronic properties of the monolayer and bulk structures of the thermoelectric material SnX(X=S,Se,Te),and the elastic properties of the bulk structure SnX are calculated and analyzed.The calculated results are consistent with the reported theoretical or experimental results.Through the calculation of energy band and density of states,it is found that SnX with monolayer and bulk structure are indirect band gap semiconductors,and the band gap decreases with the increase of the atomic number of X.According to the calculated values of elastic constant C_(ij),bulk elastic modulus B and shear modulus G of the bulk structure,it is found that SnX is mechanically stable,and they all exhibit brittleness.The elastic anisotropy factor shows that SnX has elastic anisotropy.