A DFT study of new full Heusler compound Li2MgC insights into the structural, electronic and thermoelectric properties: A high efficiency performance thermoelectric material

Abstract

Structural, electronic and thermoelectric properties for full Heusler compound Li2MgC were studied using the full potential linearized augmented plane wave (FP-LAPW) method based on the density functional theory (DFT), implemented in the Wien2k package. The term of the exchange and correlation potential (XC) is treated by the generalized gradient approximation GGA and Trans-Blaha-modified Becke–Johnson (mBJ-GGA). From the various calculations, it emerges that the Cu2MnAl type structure is more suitable for this compound than that of the Hg2CuTi type structure; moreover, this compound is stable in the non-magnetic (NM) state. Furthermore, this compound exhibits a semi -conductor behavior with an indirect band gap at Γ-X direction. The calculated formation and cohesion energies are negative, which clearly and unequivocally indicates the thermodynamic stability of the compound studied and that it can be synthesized experimentally. Otherwise, this compound is characterized by a high figure of merit (ZT) (close to unity), making it a promising candidate for thermoelectric applications.