Half-metallicity and thermoelectric performance: A multifaceted investigation of Zr-based half-Heusler alloys

Abstract

This work employs the linearized augmented plane-wave (LAPW) method within the framework of density functional theory (DFT) to explore the structural, elastic, electronic, magnetic, and thermoelectric properties of the Zr-based half-Heusler alloys CoZrSn and CoZrPb. The exchange–correlation functional is treated using both the Perdew-Burke-Ernzerhof (GGA-PBE) generalized gradient approximation and the Tran-Blaha-modified Beck-Johnson (TB-mBJ) potential, as implemented in the WIEN2k software package. Our findings indicate that the investigated material exhibits mechanical stability, suggesting its potential for experimental synthesis. Furthermore, both CoZrSn and CoZrPb display half-metallic behavior consistent with Slater-Pauling’s rule, characterized by an integer magnetic moment of 1 μB. Electronic band structures and density of states calculations, employing the TB-mBJ approximation, confirm this half-metallic character. Notably, indirect band gaps of 0.52 eV and 0.69 eV are observed for CoZrSn and CoZrPb, respectively. To investigate thermoelectric properties, including the Seebeck coefficient (S), electrical conductivity (σ), thermal conductivity (κ), and figure of merit (ZT), the Boltzmann transport equations within the DFT framework were utilized. The calculated values for the figure of merit and Seebeck coefficient suggest that the CoZrX alloys hold promise for thermoelectric applications. Significantly, there is a lack of prior experimental or theoretical investigations on the CoZrX half-Heusler alloys. Consequently, our theoretical predictions regarding the structural, elastic, electronic, magnetic, and thermoelectric properties provide valuable insights that can be further validated through future experimental studies.