Ab-initio study on Half-Heusler semiconductor PtTiSn compound: Pressure effects

Abstract

A detailed examination of the PtTiSn semiconductor Half-Heusler compound has been conducted, adopting theoretical calculations within the cubic MgAgAs-type structure. The investigation primarily focuses on elucidating the impact of pressure on various properties, including structural, mechanical, electronic, vibration, optic, and thermodynamic properties. Critical parameters such as lattice constant, volume, bulk modulus, and formation energy were rigorously analyzed at zero pressure, with comparisons between theoretical predictions and experimental data. Mechanical stability assessments indicate a ductile nature of the compound under pressure, while detailed elastic property analyses encompass Young's modulus, linear compressibility, shear modulus, and Poisson's ratio across three dimensions (3D). Electronically, the compound exhibits semiconductor behavior with an indirect bandgap. Moreover, calculations of positive phonon vibration frequencies affirm the dynamic stability of the compound within the cubic MgAgAs phase. Optical quantities covering dielectric function, refractive index, reflectivity, absorption coefficient, and loss function are provided across the infrared, visible, and ultraviolet regions. Finally, thermodynamic properties of pressure and temperature have been studied, offering insights into the compound's behavior under varying environmental conditions.