First-principles investigation of multifaceted properties; lattice dynamic, structural stability, mechanical, electronic, magnetic and thermodynamic response of Alkali metals-based semi Heusler alloys

TL;DR

This study uses first-principles calculations to explore the multifaceted properties of alkali metal-based LiVSb and NaVSb Heusler alloys, revealing their stability, electronic, magnetic, mechanical, and thermodynamic characteristics relevant for technological applications.

Contribution

It provides a comprehensive first-principles analysis of alkali metal-based Heusler alloys, including stability, electronic structure, mechanical properties, and thermodynamics, which was not previously detailed.

Findings

Alloys are dynamically stable in spin-polarized alpha phase.

Exhibit half-metallic behavior with indirect band gaps of 1.40eV and 1.45eV.

Alloys are mechanically stable and brittle, with magnetic moments following the Slater-Pauling rule.

Abstract

Taking into considerations the wide compositional stretch of Heusler alloys, the first principles density functional theory based calculations are excellently suitable for estimating the multifaceted properties of alkali metal based LiVSb and NaVSb Heusler alloys. We calculated ground state stability by optimizing the energy in alpha, beta and gamma phase configurations. The materials are dynamically stable in spin polarised phase type alpha. To explore the electronic structure, we successfully employed the generalized gradient approximation potential. The electronic band structures indicate a half-metallic nature featuring a wide indirect band gap of 1.40eV and 1.45eV. We computed the second-order elastic parameters at different pressure levels. The Pugh ratio less than 0.25 assessed that both alloys are brittle in nature and mechanically stable. The obtained magnetic moment is consistent with the Slater-Pauling rule. By executing the Quasi-Harmonic Debye model and Boltzmann theory we assessed the various thermodynamic parameters and transport coefficients of both alloys at different temperatures and pressures. All positive frequencies in lattice dynamic study confirmed their stability. Our findings highlight the potential of these alloys in modern semiconductor technology, and thermoelectric applications.