First-principles calculations to investigate structural, electronic, magnetic, thermodynamic, and thermoelectric properties of RbSrZ (Z = Ge and Sn) d0-d0 half-Heuslers for renewable energy applications

The aim of this study is to examine the thermoelectric properties alongside the structural, electronic, and magnetic properties of RbSrGe and RbSrSn d⁰-d⁰ half Heuslers. The full potential-linearized augment plane wave (FP-LAPW) system and Boltzmann transport equation are employed, utilizing classical Boltzmann approximation (CBA) in the background of density functional theory (DFT) as configured within WIEN2K. The structure optimization employed the PBE approximations and the Murnaghan equation of state, leading to a stable phase for RbSrGe and RbSrSn. The observed negative formation energy implies that the synthesis of RbSrGe and RbSrSn are possible. The half Heusler compounds under investigation were found to exhibit a narrow band gap in the majority spin direction and metallic character in the minority, which classifies these materials as half-metallic alloys based on the analysis of their electronic properties. The examination of elastic properties reveals that RbSrGe is brittle and RbSrSn is ductile. Critical analysis of thermoelectric properties demonstrates that RbSrGe and RbSrSn half Heuslers are possible materials for thermoelectrical applications.