Theoretical study of the elastic and thermodynamic properties of Pt$_{3}$Al with the L1$_{2}$ structure under high pressure

TL;DR

This study uses density functional theory to analyze the elastic and thermodynamic properties of Pt₃Al with L1₂ structure under high pressure, revealing enhanced ductility and stability with increasing pressure.

Contribution

It provides the first comprehensive theoretical analysis of Pt₃Al's elastic and thermodynamic behavior under high pressure using the quasi-harmonic Debye model.

Findings

Elastic constants increase linearly with pressure

Pt₃Al remains mechanically stable under high pressure

Higher pressure enhances ductility of Pt₃Al

Abstract

In this work, the elastic and thermodynamic properties of Pt$_{3}$Al under high pressure are investigated using density functional theory within the generalized gradient approximation. The results of bulk modulus and elastic constants at zero pressure are in good agreement with the available theoretical and experimental values. Under high pressure, all the elastic constants meet the corresponding mechanical stability criteria, meaning that Pt$_{3}$Al possesses mechanical stability. In addition, the elastic constants and elastic modulus increase linearly with the applied pressure. According to the Poisson's ratio $\nu$ and elastic modulus ratio ($B/G$), Pt$_{3}$Al alloy is found to be ductile, and higher pressure can significantly enhance the ductility. Those indicate that the elastic properties of Pt$_{3}$Al will be improved under high pressure. Through the quasi-harmonic Debye model, we first successfully report the variations of the Debye temperature $\Theta_\textrm{D}$, specific heats $C_{P}$, thermal expansion coefficient $\alpha$, and Gr\"{u}neisen parameter $\gamma$ under pressure range from 0 to 100 GPa and temperature range from 0 to 1000 K.