Structural electronic and vibrational properties analysis of Li2CaX (X = Sn, Pb) heusler alloys: a comparative study

Abstract

This study was focused on structural, electronic and vibrational properties of Li _2 CaSn and Li _2 CaPb with density functional theory. All properties of these compounds were computed by implementing General Gradient Approximation and using Quantum Espresso software programme. As a result of the calculations, it was found that the lattice parameter is 6.967 Å and bulk modulus is 33.94 GPa for Li _2 CaSn. Also, these values are 7.062 Å and 29.574 GPa for Li _2 CaPb. The calculated lattice parameters are in good agreement with the available experimental data. There is no previous theoretical calculation for Li _2 CaSn and Li _2 CaPb compounds. It was calculated that Li _2 CaSn and Li _2 CaPb have a semi-metal property. The full phonon dispersion curves of Li _2 CaSn and Li _2 CaPb compounds in the Heusler type structure were examined using the linear response method. Under 0 kbar pressure, Li _2 CaPb was unstable while Li _2 CaSn was dynamically stable. Calculations showed that when 38.42 kbar pressure is applied to the Li _2 CaPb compound, the Li _2 CaPb compound becomes dynamically stable. It is believed that this study will shape future studies.

Keywords

• Li2CaSn
• Li2CaPb
• structural properties
• vibration properties
• electronic properties
• density functional theory