Structural, electronic, mechanical and thermo-physical properties of TMN (TM = Ti, Zr and Hf) under high pressures: A first-principle study

Abstract

The ab-initio calculations have been performed to investigate the structural, electronic, elastic and thermo-physical properties of TiN, ZrN and HfN in the stable B1 and high pressure B2 phases. Two different pseudo- and full-potential based approaches have been used in the calculations. The results are in good agreement with the measured data. The elastic constants for the B2 phase of these materials have been calculated for the first time except for ZrN. The observations show that these materials are mechanically stable not only in B1 phase at ambient conditions but also in B2 phase at high pressures. They are brittle in B1 phase while ductile in B2 phase. These materials are anisotropic in both B1 and B2 phases with increased anisotropy in B2 phase. The electronic behaviour of these materials is similar in both B1 and B2 phases except the broadening of the bands in B2 phase. These materials are found to be covalent, ionic and metallic in both the phases concerned. Present observation of electronic nature in CsCl structure of these materials needs validation by future researchers.