ZnSe高压物性的第一性原理研究

First-principles study of high-pressure physical properties of ZnSe

摘要:

采用基于密度泛函理论的第一性原理方法，研究了ZnSe的三种结构岩盐结构（RS）、闪锌矿结构（ZB）及六方纤锌矿结构（WZ）的结构性质. 通过等焓原理得到ZnSe从ZB结构转变为RS结构的相变压强约为15.5 GPa，与实验值符合得比较好. 计算出ZnSe不同压力下ZB结构的弹性常数，通过准谐德拜模型得到不同温度下ZB结构的热膨胀系数与压强的关系等热力学性质.

Abstract:

Using the first-principles method based on density functional theory we study the structural properties of zinc-blende structure, rocksalt structure and hexagonal wurtzite structure of ZnSe. At the same time, according to the isoenthalpy principle, we have found the transition pressure from zinc-blende to rocksalt is about 15.5 GPa, which is in good agreement with the experimental result. The elastic constants of ZnSe with zinc-blende structure under different pressures are calculated. The relationship between the thermal expansion coefficient and the pressure at different temperatures are obtained based on the quasi-harmonic Debye model.