Investigating the structural, electronic, and elastic properties of Li-based quaternary Heusler alloy semiconductors using hybrid functional – HSE06 bandgap recalculations

Abstract

In this work, we introduce a new class of stable semiconducting equiatomic quaternary Heusler alloys. The 21 new semiconductors reported in this work contain 18 valence electrons per unit cell.Three different structural arrangements, referred Y1,Y2 and Y3 are taken into consideration. The bandgaps are investigated and significantly underestimated by GGA-PBE functional. We recalculated them by means of the Heyd-Scuseria-Ernzerhof (HSE06) hybrid functional to achieve the correct ones. This study shows that the HSE06 correction mainly acts on the lowest conduction bands. The energy gaps of the quaternary Heusler semiconductors are in the range of 0.766–1.94 eV, which suggests that these semiconductors are prospective materials for a variety of applications, including thermoelectric, optoelectronic, and photovoltaic. Furthermore, formation energy, elastic constants, and phonon dispersion curves are calculated to verify the mechanical and dynamical stabilities of these alloys.