Structural, elastic, electronic and optical properties of the half-Heusler ScPtSb and YPtSb compounds under pressure

TL;DR

This study uses first-principles calculations to analyze how pressure affects the structural, elastic, electronic, and optical properties of half-Heusler compounds ScPtSb and YPtSb, revealing their stability and electronic behavior.

Contribution

It provides a comprehensive first-principles analysis of pressure effects on the properties of ScPtSb and YPtSb, including electronic band structure and optical responses, with inclusion of spin-orbit coupling.

Findings

ScPtSb has an indirect band gap of Γ-X type.

YPtSb has a direct band gap of Γ-Γ type.

Optical properties vary with pressure, affecting dielectric function and reflectivity.

Abstract

First-principles calculations using the plane-wave pseudopotential method within the generalized gradient approximation method were performed to study the pressure dependence of the structural, elastic, electronic and optical properties for the half-Heusler compounds ScPtSb and YPtSb in a cubic MgAgAs-type structure. The calculations were performed with the inclusion of spin-orbit coupling. The calculated equilibrium lattice parameters are in good agreement with the available experimental and theoretical values. The crystal rigidity and mechanical stability were discussed using the elastic constants and related parameters, namely bulk modulus, shear modulus, Debye temperature, Poisson's coefficient, Young's modulus and isotropic sound velocities. The calculated electronic band structures show that ScPtSb has an indirect gap of $\Gamma-X $ type, whereas YPtSb has a direct band gap of $\Gamma -\Gamma $ type. Furthermore, the effect of pressure on the optical properties, namely the dielectric function, absorption spectrum, refractive index, extinction coefficient, reflectivity and energy-loss spectrum is investigated for both compounds ScPtSb and YPtSb.