中国物理B ›› 2014, Vol. 23 ›› Issue (2): 26201-026201.doi: 10.1088/1674-1056/23/2/026201
• CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES • 上一篇 下一篇
濮春英a, 周大伟a, 包代小b, 卢成a, 靳希联c, 宿太超d, 张飞武e
Pu Chun-Ying (濮春英)a, Zhou Da-Wei (周大伟)a, Bao Dai-Xiao (包代小)b, Lu Cheng (卢成)a, Jin Xi-Lian (靳希联)c, Su Tai-Chao (宿太超)d, Zhang Fei-Wu (张飞武)e
摘要: By the particle-swarm optimization method, it is predicted that tetragonal P42mc, I41md, and orthorhombic Amm2 phases of vanadium nitride (VN) are energetically more stable than NaCl-type structure at 0 K. The enthalpies of the predicted three new VN phases, along with WC, NaCl, AsNi, CsCl type structures, are calculated each as a function of pressure. It is found that VN exhibits the WC-to-CsCl type phase transition at 256 GPa. For the considered seven crystallographic VN phases, the structures, elastic constants, bulk moduli, shear moduli, and Debye temperatures are investigated. Our calculated equilibrium structural parameters are in very good agreement with the available experimental results and the previous theoretical results for the NaCl phase. The Debye temperatures of VN predicted three novel phases, which are all higher than those of the remaining structures. The elastic constants, thermodynamic properties, and elastic anisotropies of VN under pressure are obtained and the mechanical stabilities are analyzed in detail based on the mechanical stability criteria. Moreover, the effect of metallic bonding on the hardness of VN is also investigated, which shows that VNs in P42mc, I41md, and Amm2 phases are potential superhard phases. Further investigation on the experimental level is highly recommended to confirm our calculations presented in this paper.
中图分类号: (Elasticity)