Ca5Zn3相稳定性和物理性质的第一性原理研究

利用基于密度泛函理论的第一性原理方法对Ca_5Zn_3化合物的晶格常数、形成焓、弹性常数、以及电子态密度等进行计算研究。为了获得Ca_5Zn_3化合物的结构稳定性,考虑了Cr_5B_3、W_5Si_3以及Mn_5Si_3 3种结构类型,计算得到的形成焓表明:具有Cr5B3结构类型的Ca_5Zn_3最稳定,其次为Mn_5Si_3型,最后是W_5Si_3型。对该化合物的弹性常数、电子态密度和电荷密度差进行了计算。最后利用德拜模型,对Ca_5Zn_3的热物理性能进行了计算,获得体积、体积模量、热膨胀系数以及等容热容随温度和压强变化的规律,为该化合物在热电方面的应用提供了理论依据。

Phase Stability and Physical Properties of Ca5Zn3 Compound by Using First-principles

Using the first-principles method based on density functional theory, the lattice constants, formation enthalpy, elastic constants, and electronic state densities of Ca₅Zn₃ compounds were calculated and studied. In order to obtain the structural stability of Ca₅Zn₃ compounds, three structural types of Cr₅B₃,W₅Si₃ and Mn₅Si₃ were considered. The calculated formation enthalpies indicate that Ca₅Zn₃ with Cr₅B₃ structure type is the most stable, followed by Mn₅Si₃ type, and finally is W₅Si₃ type. The elastic constants, electronic state densities and charge density difference of Ca₅Zn₃ compound were calculated. Finally, using the Debye model, the thermo-physical properties of Ca₅Zn₃ were calculated, and the laws of volume, bulk modulus, thermal expansion coefficient and isochoric heat capacity with temperature and pressure were obtained. It provides a theoretical basis for the application of this compound in thermoelectric field.