高压下硫化钙的弹性和热力学性质的第一性原理计算

计算物理 ›› 2017, Vol. 34 ›› Issue (4): 468-474.

高压下硫化钙的弹性和热力学性质的第一性原理计算

牛兴平, 孙兆楼

安阳工学院数理学院, 河南安阳 455000

收稿日期:2016-05-24 修回日期:2016-09-08 出版日期:2017-07-25 发布日期:2017-07-25
作者简介:牛兴平(1977-),男,硕士,讲师,研究方向:材料物理化学性质等,E-mail:niuxingping@sina.com
基金资助:
国家自然科学基金（11447150）资助项目

First Principles Study on Elastic and Thermodynamic Properties of CaS

NIU Xingping, SUN Zhaolou

School of Mathmatics and Physics, Anyang Institute of Technology, Anyang 455000, China

Received:2016-05-24 Revised:2016-09-08 Online:2017-07-25 Published:2017-07-25

摘要/Abstract

摘要： 利用基于密度泛函理论的第一性原理平面波赝势方法结合准谐德拜模型研究NaCl结构的CaS在高压下的弹性和热力学性质.计算得到的零温零压下的晶格常数、体弹模量与实验值符合得很好.弹性常数和弹性模量随着压强的增大而增大.压强对体弹模量和热膨胀系数的影响大于温度的影响.热容随压强的升高而降低，在高温下热容接近于Dulong-Petit极限.通过求解Gibbs自由能计算得到B1结构和B2结构CaS的相变压为36.61 GPa.

关键词: 第一性原理, 弹性性质, 体弹模量, 热力学性质

Abstract: First-principles calculations of elastic and thermodynamic properties of CaS in NaCl structure under high pressures are conducted by using plane-wave pseudopotential density functional theory method and quasi-harmonic Debye model. Calculated lattice constants and elastic modulus at P=0 GPa and T=0 K are in good agreement with experimental data. It shows that influence of pressure on elastic modulus and thermal expansion coefficient is greater than that of temperature. Heat capacity decreases with increase of pressure under same temperature and tends to Dulong-Petit limit at high temperatures. By solving Gibbs free energy, phase transition pressure between B1 structure and B2 structure of CaS is obtained at 36.61 GPa.

Key words: first principles, elastic properties, elastic modulus, thermodynamic properties

中图分类号:

TB303

牛兴平, 孙兆楼. 高压下硫化钙的弹性和热力学性质的第一性原理计算[J]. 计算物理, 2017, 34(4): 468-474.

NIU Xingping, SUN Zhaolou. First Principles Study on Elastic and Thermodynamic Properties of CaS[J]. CHINESE JOURNAL OF COMPUTATIONAL PHYSICS, 2017, 34(4): 468-474.

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