Rattling Heusler semiconductors' thermoelectric properties: First-principles prediction

Abstract

First-principles full-potential linearized augmented plane-wave method based on density functional theory is used to investigate the structural, electronic, thermoelectric and thermodynamic properties of the cubic Rattling Heusler (RH) Ba2AuZ (where Z = Bi, Sb), within the local density approximation (LDA) and generalized gradient approximation (GGA) for potential exchange correlation. The modified Becke-Johnson (mBJ) potential approximation is also used for calculating the electronic band structure and density of states of the full-Heusler compounds Ba2AuSb and Ba2AuBi. We have analyzed the structural parameters, total and partial densities of states (TDOS and PDOS). The results show that the electronic property of these cubic Rattling Heusler alloys have a semiconducting behavior with indirect band gaps using both GGA-PBE and mBJ-GGA. Through the quasi-harmonic Debye model, in which the effect of pressure P (0 to 9 GPa) and temperature T (0 to 1200 K) on the volume V, heat capacity Cv, entropy S and Debye temperature θD are investigated.The very important value of the merit factor (ZT) and Seebeck coefficient (S) make these compounds promising candidates for thermoelectric applications.