Theoretical investigation of half-Heusler compound XYZ (X=Li, Na, K; Y=Ba; Z=B) for spintronic and thermoelectric applications

Abstract

Density functional theory with pesudo potential approximation is used to study XBaB ([Formula: see text], Na, K) half-Heusler compounds structural, magnetic and electrical property using Quantum espresso code and thermoelectric properties were studied using BoltzTrap code. Total energy calculations were carried out in the [Formula: see text], [Formula: see text] and [Formula: see text] phases of XBaB compounds in [Formula: see text] type structure. The compounds were stable in [Formula: see text]-phase and hence further calculations were focused only on [Formula: see text] phase. From the spin polarization calculations, magnetic state was stable than nonmagnetic state and exhibits ferromagnetism at the equilibrium lattice constant with an integer magnetic moment of 2 [Formula: see text]. From the band structure calculations and through density of states, all the three compounds exhibit half-metallicity with 100% spin polarization by showing semi-conductivity for majority spin and metallicity for minority spin. In addition, thermoelectric properties were investigated for all three compounds. LiBaB is found to have high Seebeck coefficient of 2462[Formula: see text][Formula: see text]VK[Formula: see text] and ZT value of 1, compared to other compounds. These materials were found to have high ZT value and hence they can be used for thermoelectric applications.