研究简报Nb_2N_3的力学和电子性质的第一性原理

A First-Principles of Elastic and Electronic Properties of Nb_2N_3

采用基于密度泛函理论的第一性原理方法研究Nb2N3的晶体结构、力学、晶格动力学和电子性质.结果表明:Nb2N3常压下具有正交η-Ta2N3结构,其弹性常数满足波恩-黄昆判据,且晶格动力学稳定;Nb2N3具有较大的体弹性模量(304 GPa)和硬度(19.3 GPa),由于Nb 4d轨道与N 2p轨道杂化形成三维Nb-N共价键,因此Nb2N3为离子性较强的半导体材料.

The crystal structure,dynamics,lattice dynamics,and electronic properties of Nb2N3 were studied by means of first-principles method of the density functional theory.The results show that Nb2N3 has orthogonal η-Ta2N3 structure at normal pressure,the elastic constants of this structure meet the Bonn-Huangkun criterion,and its lattice is dynamics stable.Nb2N3 has large bulk modulus（304 GPa） and hardness（19.3 GPa）.Because of the hybridization of 4d orbital of Nb and 2p orbital of N forming three-dimensional Nb-N covalent bonds,Nb2N3 is ionic semiconductor materials.