Study of thermoelectric, electronic, thermo-elastic and thermodynamic properties of LiYN (Y = Mg and Ca) half Heusler semiconductors at high-temperature

Abstract

In this study, we use first-principles computational methods to investigate the structural, thermo-elastic stability, electronic and thermoelectric properties of LiYN (Y = Mg and Ca) half Heusler. The obtained results show that the compounds are structurally stable in α-LiYN phase and exhibit semiconductor behavior with band gap values of 2.412 eV (3.883 eV) and 2.340 eV (3.980 eV) when employing GGA (HSE) approach, respectively. The findings of the temperature dependence of the elastic constants illustrate the mechanical stability at high temperatures of α-LiYN, and they have a high melting temperature of 2034 K and 1544 K for LiMgN and LiCaN, respectively, which makes them more important in high temperature applications. Based on the thermoelectric results, we can also conclude that these compounds are promising for thermoelectric devices at high temperatures.