Theoretical insights into the physical properties of a new 211 MAX phase V2ZnC under high pressure

Abstract

Based on the first principles of density functional theory, the effects of pressure on the crystal structure, elastic, electronic, thermodynamic stability and thermodynamic properties of the novel MAX phase V2ZnC were investigated. The elastic constants and phonon dispersion calculations indicated that V2ZnC is mechanically and dynamically stable in the pressure range 0–40 GPa. The enthalpy of formation calculation shows that V2ZnC is thermodynamically stable at a given pressure range, and pressure can improve the thermodynamic stability of V2ZnC. The calculated elastic constants and elastic modulus of V2ZnC increase with increasing pressure. In addition, pressure can improve the stiffness and elastic anisotropy of V2ZnC. Calculation of Poisson's ratio and B/G revealed a significant transition in the mechanical behavior of V2ZnC from brittleness to ductility at a pressure of 20 GPa. The analysis of the band structure and density of states confirms the metallic nature of V2ZnC. Under increasing pressure, a notable decrease in the electron state density at the Fermi level is observed, leading to an enhanced stability of V2ZnC. Furthermore, a systematic investigation of the thermophysical properties of V2ZnC under high pressure (0–40 GPa) has been conducted. It was found that the Debye temperature and melting point increase with the increase of pressure, indicating that the effective role of pressure in modulating the thermophysical characteristics of V2ZnC.