Ya-Ru Zhao, Hai-Rong Zhang, Gang-Tai Zhang, Qun Wei, Yu-Quan Yuan
College of Physics & Optoelectronics Technology, Baoji University of Arts and Sciences , Baoji 721016, China.
School of Electrical and Electronic Engineering, Baoji University of Arts and Sciences , Baoji 721016, China.
AIP Adv. 2016 Dec 16;6(12):125040. doi: 10.1063/1.4972775. eCollection 2016 Dec.
The elastic anisotropy and thermodynamic properties of the recently synthesized -CN have been investigated using first-principles calculations under high temperature and high pressure. The calculated equilibrium crystal parameters and normalized volume dependence of the resulting pressure agree with available experimental and theoretical results. Within the considered pressure range of 0-90 GPa, the dependences of the bulk modulus, Young's modulus, and shear modulus on the crystal orientation for -CN have been systematically studied. The results show that the -CN exhibits a well-pronounced elastic anisotropy. The incompressibility is largest along the -axis. For tension or compression loading, the -CN is stiffest along [001] and the most obedient along [100] direction. On the basis of the quasi-harmonic Debye model, we have explored the Debye temperature, heat capacity, thermal expansion coefficient, and Grüneisen parameters within the pressure range of 0-90 GPa and temperature range of 0-1600K.
利用高温高压下的第一性原理计算，研究了最近合成的-CN的弹性各向异性和热力学性质。计算得到的平衡晶体参数以及由此产生的压力的归一化体积依赖性与现有的实验和理论结果一致。在0-90 GPa的考虑压力范围内，系统地研究了-CN的体模量、杨氏模量和剪切模量对晶体取向的依赖性。结果表明，-CN表现出明显的弹性各向异性。沿轴方向的不可压缩性最大。对于拉伸或压缩加载，-CN在[001]方向最硬，在[100]方向最柔顺。基于准谐德拜模型，我们在0-90 GPa压力范围和0-1600K温度范围内研究了德拜温度、热容、热膨胀系数和格林爱森参数。
