Nb_2AsC结构及热力学性质的第一性原理研究  

Ab Initio Calculation of Structural and Thermodynamic Properties of Nb_2AsC

作　　者：罗雰 郭志成[1] 李登峰 张伟[3,4] LUO Fen;GUO Zhi-cheng;LI Deng-feng;ZHANG Wei(Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology Mianyang Sichuan 621900;Department of Mathematics and Physics, Chongqing University of Posts and Telecommunications Nan’an Chongqing 400065;School of Science, Southwest University of Science and Technology Mianyang Sichuan 621900;Laboratory for Shock Wave and Detonation Physics Research, Institute of Fluid Physics, Chinese Academy of Engineering Physics Mianyang Sichuan 621900)

机构地区：[1]西南科技大学极端条件物质特性实验室,四川绵阳621900 [2]重庆邮电大学理学院,重庆南岸400065 [3]西南科技大学理学院,四川绵阳621900 [4]中国工程物理研究院流体物理研究所冲击波物理与爆轰物理重点实验室,四川绵阳621900

出　　处：《电子科技大学学报》2017年第6期856-860,共5页Journal of University of Electronic Science and Technology of China

基　　金：国家自然科学基金(11604272;11447176;11447152;11347134)

摘　　要：采用基于密度泛函理论的第一性原理方法研究Nb2AsC的结构、弹性和热力学性质,与其他实验值和理论值相比,该文计算的Nb2AsC晶体结构常数、体弹模量及其对压力的一阶偏导均与之符合较好;计算获得的常压弹性常数与其他理论值比较一致,由此根据力学稳定性准则,判定六方晶系Nb2AsC是力学稳定结构。预测了Nb2AsC的杨氏模量。结果表明,六方晶系Nb2AsC是各向异性。采用准谐德拜模型,模拟了压力和温度对Nb2AsC的等容热容、等温弹性模量、热膨胀系数和德拜温度等热力学性质的影响。The structural and thermodynamic properties of Nb2AsC have been investigated with the first-principles density functional theory computations.The calculated equilibrium structural parameters agree well with the available experimental and theoretical values of Medkour et al.The calculated elastic constants are in excellent agreement with the theoretical values at ambient pressure.The elastic constant indicates that hexagonal structure Nb2AsC is mechanically stable at ambient pressure.Also,the elastic anisotropy is examined through the computation of the Young’s modulus.Based on quasi-harmonic Debye model,the thermodynamic properties including the adiabatic bulk modulus,thermal expansion coefficient,Debye temperature and heat capacity at constant volume under high temperature and pressure are predicted.

关 键 词：密度泛函理论 弹性性质 热力学性质 准谐德拜模型 

分 类 号：O52[理学—高压高温物理]