Investigation on Structural, Elastic, Electronic and Vibrational Properties of LiTiAl Half-Heusler Compound Using First Principles Methods

Abstract

Heusler alloys are particularly noticeable in spintronics and thermoelectric applications. The researches on new and better thermoelectric materials are increasing rapidly due to the energy crisis and environmental pollution which are frequently discussed in recent times. Thermoelectric materials are seen as potential ways to solve these problems. Half-Heusler materials are considered thermoelectric materials due to their large temperature stability. Typically, half-Heusler crystallizes in a face-centered cubic structure with alloys space group (No.216). In this study, the structural, elastic, electronic and vibrational properties of the Li-based LiTiAl compound with 8 electrons in the primitive cell were investigated using the VASP package program using the first principles methods. The 700 eV cutoff energy and 15x15x15 k-points were used in calculations. The lattice constant has been calculated as 6.191Å. The obtained structural parameteres are convenient with the results of literature. Band structures, total and partial density states graphs are drawn as electronic properties. From these calculations, the band gap of this compound was found to be 9.55 meV. Elastic constants were calculated from stress-strain rate. The calculated elastic constants show that this compound is mechanically stable. Phonon frequencies are calculated and the structure is found dynamically stable.