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) Ba 2 AuZ (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 Ba 2 AuSb and Ba 2 AuBi. 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 C v , entropy S and Debye temperature θ D are investigated. The very important value of the merit factor (ZT) and Seebeck coefficient (S) make these compounds promising candidates for thermoelectric applications.