Prediction the Structural, Electronic, Elastic and Dynamical Properties of Lialge and Liinge Half-Heusler Crystals by Density Functional Theory

Abstract

In the present study, structural, electronic, elastic and vibrational properties of LiInGe and LiAlGe half-Heusler compounds are investigated using density functional theory implemented in ABINIT and Quantum ESPRESSO programs. Generalized gradient approximation as an exchange correlation functional is used in Kohn-Sham equations to find lattice parameters, energy band gaps and three elastic constants C-11, C-12 and C-44 for LiInGe and LiAlGe crystals. Density functional perturbation theory has been adopted in the study of lattice dynamics. As a result of the calculations, it is concluded that the phonon dispersion curves have positive frequency values throughout the entire Brillouin region and the dynamic stability of both crystals is strong. It is estimated as a result of calculations that this stabilization is impaired at a pressure value of approximately 492.65 kbar for LiInGe crystal and approximately 962.16 kbar for LiAlGe crystal.