TiB_2热力学性质的第一性原理研究

First Principles Study of the Thermodynamic Properties of TiB_2

利用第一性原理方法并结合准德拜模型计算了六方结构TiB2在高温高压下的热力学性质,包括常压下晶格常数、体弹模量B0、热容Cp和熵S随温度的变化以及不同压强下热容Cp、熵S、体膨胀系数α、德拜温度Θ和热容CV与温度的关系.常压下计算的热容Cp和熵S随温度的变化与实验数据符合很好.

The thermodynamic properties of hexagonal TiB2 at high temperature and pressure are calculated by using first principles combined with quasi-harmonic Debye model,including the temperature dependence of the lattice parameter,the bulk modulus B0,the heat capacity Cp and the entropy S under ambient pressure.Meanwhile,the relationship of the temperature with the heat capacity Cp,the entropy S,the coefficient of volume expansion α,the Debye temperature Θ and the heat capacity CV expansion coefficient under different pressures is successfully obtained.The results show the calculated heat capacity Cp and entropy S under ambient pressure are in good agreement with experimental measurements.