The Structural, Elastic, Electronic, Thermodynamic and Vibrational Properties of Protactinium Monocarbide (PaC) from First-Principles Calculations

Abstract

The structural, elastic, electronic, thermodynamic, and vibrational properties of protactinium monocarbide (PaC), which crystallizes in NaCl-type phase (B1), were studied by performing ab-initio calculations based on density functional theory with in the generalized gradient approximation (GGA) using the Vienna Ab-initio Simulation Package (VASP). The calculated structural parameters, such as lattice constant, bulk modulus and its pressure derivative, formation energy were presented for B1 and B2 structures. This compound exhibits crystallographic phase transition from NaCl-type (B1) to CsCl-type (B2) structure at 42.7 GPa pressure. In order to gain further information, we investigated the elastic properties such as, Zener anisotropy factor, Poisson's ratio, Young's modulus, and isotropic shear modulus; the thermodynamic properties such as, the pressure and temperature dependent behavior of the normalized volume, bulk modulus, thermal expansion coefficient, heat capacity, Debye temperature, Gruneisen parameter, and entropy over a pressure range of 0-40 GPa and a temperature range of 0-2000 K. The electronic band structure, total density of states, phonon dispersion curves and one-phonon density of states of B1 phase were also presented.