Abstract:

The crystal structure, dynamics, lattice dynamics, and electronic properties of Nb₂N₃ were studied by means of  first\|principles method of the density functional theory. The results show that Nb₂N₃ has orthogonal η-Ta₂N₃ structure at normal pressure, the elastic constants of this structure meet the Bonn\|Huangkun criterion, and its lattice is dynamics stable. Nb₂N₃ has  large bulk modulus （304 GPa） and hardness （19.3 GPa）. Because of the hybridization of 4d orbital of Nb and 2p orbital of N forming three\|dimensional Nb\|N covalent bonds, Nb2N3 is ionic semiconductor materials.

Key words: niobium nitride, hard material, high pressure physics