Elastic properties of 5d transition-metal carbides: An ab initio study

TL;DR

This study uses ab initio calculations to analyze the elastic properties and stability of 5d transition-metal carbides in different crystal phases, revealing phase-dependent stability patterns.

Contribution

It provides a systematic computational analysis of the mechanical stability of group V transition metal carbides in pyrite and fluorite phases, identifying stable and unstable compounds.

Findings

Most carbides are stable in pyrite phase.

All studied carbides are unstable in fluorite phase.

ReC$_2$ and OsC$_2$ are unstable in pyrite phase.

Abstract

We have systematically studied the mechanical stability of group V transition metal carbides TMC$_2$ (TM = Hf, Ta, W, Re, Os, Ir, Pt, and Au) in the pyrite and fluorite phase, by calculating their elastic constants within the density functional theory scheme. It was found that all but ReC$_2$ and OsC$_2$ are stable in pyrite phase. On the other hand, all metal carbides studied were unstable in the fluorite phase.