Cd3As2弹性模量和热力学性质模拟研究

Theoretical study on elastic modulus and thermodynamic properties of Cd3As2

摘要:

利用第一性原理结合赝势平面波方法研究了立方（空间群：P4232, No:208）和四方（空间群：P42/nmcs, No:137）Cd3As2的晶体结构、状态方程、弹性常数. 将晶胞能量-体积关系按Birch–Murnaghan状态方程拟合得到体弹模量及其对压强的一阶导数. 另外，根据Voigt–Reuss–Hill关系预测了Cd3As2晶体的力学性质. 最后，通过准谐德拜模型得到Cd3As2晶体在不同温度下的热膨胀系数、绝热体弹模量、晶胞体积和等体热容.

Abstract:

We have performed theoretical investigations on the structure, equation of state (EOS), elasticity of the cubic ( space group of P4232, No: 208) and tetragonal ( space group of P42/nmcs, No: 137) Cd3As2 crystal by using the first-principles pseudopotential plane-wave method. The bulk modulus and its pressure derivation are obtained by fitting the energy–volume points to Birch–Murnaghan equation of state. Moreover, according to the Voigt–Reuss–Hill approximation, the elastic moduli of Cd3As2 are also successfully predicted. By employing the quasi-harmonic Debye model, the thermal expansion coefficient, bulk modulus, cell volume and heat capacity at different temperatures are also obtained.