First-principles calculations of Mg_2X(X =Si,Ge,Sn) semiconductors with the calcium fluorite structure

作     者：郭三栋 

作者机构：Department of PhysicsSchool of SciencesChina University of Mining and Technology 

出 版 物：《Journal of Semiconductors》 (半导体学报（英文版）)

年 卷 期：2015年第36卷第5期

页      面：8-13页

核心收录：

学科分类：080903[工学-微电子学与固体电子学] 0809[工学-电子科学与技术（可授工学、理学学位）] 08[工学] 080501[工学-材料物理与化学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 

基　　金：Project supported by the Fundamental Research Funds for the Central Universities(No.2013QNA32) the National Natural Science Foundation of China(No.11404391) 

主　　题：semiconductor optical properties elastic properties phonon 

摘      要：The electronic structures ofMg2X （X = Si, Ge, Sn） have been calculated by using generalized gradient approximation, various screened hybrid functionals, as well as Tran and Blaha＇s modified Becke and Johnson exchange potential. It was found that the Tran and Blaha＇s modified Becke and Johnson exchange potential provides a more realistic description of the electronic structures and the optical properties of MgEX （X = Si, Ge, Sn） than else exchange-correlation potential, and the theoretical gaps and dielectric functions of Mg2X （X = Si, Ge, Sn） are quite compatible with the experimental data. The elastic properties of Mg2X （X = Si, Ge, Sn） have also been studied in detail with the generalized gradient approximation, including bulk modulus, shear modulus, Young＇s modulus, Poisson＇s ratio, sound velocities, and Debye temperature. The phonon dispersions ofMg2X （X = Si, Ge, Sn） have been calculated within the generalized gradient approximation, suggesting no structural instability, and the measurable phonon heat capacity as a function of the temperature has been also calculated.