A First Principle Study of Pressure Induced Structural and Electronic Properties in Neptunium Bismuthide

Abstract

We have examined the pressure induced structural and electronic   properties of neptunium monobismuthides. The total energy as a function of volume is obtained by means of self-consistent tight binding linear muffin-tin-orbital (TB-LMTO) method within the local density approximation (LDA). It is found that NpBi is stable in NaCl – type structure under ambient pressure. We predict a structural phase transition from NaCl-type (B₁-phase) sructure to CsCl-type (B₂-phase) structure for NpBi in the pressure range of 11 GPa. We also calculate the lattice parameter (a₀), bulk modulus (B₀), band structure and density of states. From energy band diagram it is observed that NpBi exhibit metallic behaviour. The calculated equilibrium lattice parameters and bulk modulus are in general good agreement with available experimental data.

Keywords: Structural phase transition; Electronic band structure; Metallic.