Investigation of Structural, Elastic, Thermodynamic Properties and Phonon Dispersion of Heusler Alloys XYSb (X = Li2 and Ru, Y = Na and Ta) Using First Principles Calculations

Abstract

Abstract This study presents a comprehensive density functional theory examination of Li2NaSb and RuTaSb Heusler alloys, exploring structural, elastic, thermodynamic, and phonon dispersion properties. Quantum ESPRESSO and Thermo_pw calculations reveal optimized lattice constants of 6.8603 Å and 6.1608 Å for Li2NaSb and RuTaSb, respectively. Poisson’s ratio values of 0.16 for Li2NaSb and 0.32 for RuTaSb indicate that the materials exhibit brittleness and ductility, respectively. Anisotropic values 2.29 and 1.04 for Li2NaSb and RuTaSb, respectively, confirm material directionality. Thermodynamic analysis reveals an increase in vibrational energy, a decrease in free energy, and an increase in entropy as temperature increases. Phonon dispersion calculations demonstrate the materials' dynamic stability. The results obtained for Li2NaSb and RuTaSb have not been reported in any literature.