High-pressure phase transitions in transition metal carbides XC (X = Ti, Zr, Hf, V, Nb, Ta): a first-principle study

Abstract

First-principle density functional approach has been applied to study the B1→B2 structural phase transition in transition metal carbides (TMCs) (XC; X = Ti, Zr, Hf, V, Nb, and Ta) under the application of pressure. The computations have been performed using ground state total energy calculation approach of the system. The study computes the stability of structure as a function of pressure in original rocksalt (B1) and hypothetical CsCl (B2)-type phases using generalized gradient approximation with Perdew–Burke–Ernzerhof-type parametrization and local density approximation with Ceperley–Alder-type parametrization as exchange correlation functional and observed that the vanadium carbide is found to be the most stable amongst all the carbides taken into consideration. Pressure of more than 400 GPa transforms the original B1-type phase of these carbides to a B2-type phase. We have also calculated the ground state properties, such as lattice constant (a), bulk modulus (B ₀), and pressure derivative of bulk modulus () of TMCs.

Keywords:

• phase transition
• transition metal carbides
• high pressure
• first principle
• rocksalt
• CsCl

Acknowledgement

The authors gratefully acknowledge the DRDO for providing financial support for the research. One of the authors, Mamta Chauhan, is grateful to DRDO for providing JRF.