物理化学学报 >> 2010, Vol. 26 >> Issue (01): 13-17.doi: 10.3866/PKU.WHXB20100106

热力学、热化学和溶液化学 上一篇    下一篇

闪锌矿ZnTe高温高压下的弹性及热力学性质

吕冉, 高涛, 李喜波, 罗江山, 唐永建   

  1. 四川大学原子与分子物理研究所, 成都 610065; 中国工程物理研究院激光聚变研究中心, 四川 绵阳 621900
  • 收稿日期:2009-07-14 修回日期:2009-09-01 发布日期:2009-12-29
  • 通讯作者: 高涛 E-mail:gaotao@scu.edu.cn

Elastic and Thermodynamic Properties of Zinc-Blende ZnTe under High Temperature and Pressure

LV Ran, GAO Tao, LI Xi-Bo, LUO Jiang-Shan, TANG Yong-Jian   

  1. Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065, P. R. China; Research Centre of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900, Sichuan Province, P. R. China
  • Received:2009-07-14 Revised:2009-09-01 Published:2009-12-29
  • Contact: GAO Tao E-mail:gaotao@scu.edu.cn

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摘要：

利用第一性原理平面波赝势密度泛函理论并结合准谐德拜模型计算了闪锌矿结构ZnTe在高温高压下的弹性及热力学性质. 得到了绝对零度、零压强时的晶格常数为0.6095 nm, 仅比实验值(0.6103 nm)小0.1%. 计算的体弹模量及弹性常数也与实验值符合较好. 根据计算的高压下的弹性常数, 得到其相变点约为10 GPa, 与已知的实验值一致. 通过准谐德拜模型, 得到了常温下(T=300 K)的德拜温度为249 K, 并得到了不同温度、不同压强下的热容. 热容随着压强增加而减小,在高温、高压下, 热容接近于Dulong-Petit极限.

关键词: ZnTe, 弹性常数, 相变, 热力学性质, 准谐德拜模型

Abstract:

First-principles theoretical study of the elastic and thermodynamic properties of ZnTe in zinc-blende (ZB) structure at high temperature and pressure was performed by using the plane-wave pseudopotential method. The calculated lattice parameter of 0.6095 nm is in excellent agreement with the experimental value of 0.6103 nm and is only 0.1% smaller. The elastic constants and bulk modulus at p =0 GPa and T =0 K are also in agreement with experimental data. From the values of the elastic constants at high pressures, the transition pressure is about 10 GPa judged by the mechanical stability conditions of cubic crystals and this is consistent with available experimental data. The Debye temperature (249 K) at the normal temperature (T=300 K) and the values for heat capacity (CV) at different pressures and temperatures were also obtained by applying the quasi-harmonic Debye model. We found that the CV decreased with the increase of pressure and was close to the Dulong-Petit limit at high temperature and pressure.

Key words: ZnTe, Elastic constant, Phase transition, Thermodynamic property, Quasi-harmonic Debye model