黄铜矿MgGeP2的几何结构，弹性性质和热学性质的研究

Study on The Structural, Elastic and Thermal Properties of Chalcopyrite MgGeP2

摘要:

利用第一性原理的密度泛函方法对MgGeP2结构性质，弹性性质和热力学性质进行了系统的研究，得到了平衡态的晶格常数，能带带隙，弹性系数和其他相关的热力学参数.通过对结果进行理论分析发现：MgGeP2在零压下属于直接带隙半导体，带隙值为1.522eV.而弹性性质计算说明MgGeP2是各向异性且具有良好塑性的材料.此外，利用准谐德拜模型计算了0~40GPa的压强和0~800K的温度下热膨胀系数，热熔Cv和Cp，熵和德拜温度的变化趋势，理论计算结果和实验值符合很好.

Abstract:

The structural, elastic and thermal properties of MgGeP2 crystal have been studied comprehensively with the first-principle based on the density function theory. The equilibrium lattice constant, the energy gap, the elastic coefficient and other related thermal parameters of MgGeP2 have been discussed in this paper. The results are analyzed theoretically and show that the compound of MgGeP2 at zero-pressure is direct band-gap semiconductor and the value of energy gap is 1.522eV. Furthermore, Calculation of elastic properties in this crystal indicates the MgGeP2 is an anisotropic and ductile material. In addition, the effect of temperature and pressure thermal properties such as Debye temperature, the thermal expansion coefficient, the heat capacity Cv and Cp are also worked out by the quasi-harmonic Debye model in the rang of 0~40GPa and 0~800K.