First-principles investigation of physical, mechanical, thermodynamics and transport properties of tetragonal double perovskite Sr2MnSbO6: A DFT+U+SOC study

Abstract

In this study, we investigate the structural, electronic, elastic, and thermoelectric properties of the tetragonal Sr₂MnSbO₆ double perovskite using the full-potential linearized augmented plane wave (FP-LAPW) method within the WIEN2k code. The calculations were performed using the generalized gradient approximation (GGA-PBE), GGA-PBE + U, and the Tran-Blaha modified Becke-Johnson (TB-mBJ) potential to correct the exchange-correlation functional. Spin-orbit coupling (SOC) was applied to account for relativistic effects. The results confirm the stability of the ferromagnetic (FM) state, as evidenced by energy optimization. Notably, the compound exhibits robust half-metallicity, characterized by a semiconductor nature in the spin-down channel and metallic behavior in the spin-up channel, which is a key feature for efficient spintronic applications such as spin filters and magnetic sensors. Thermodynamic stability is affirmed by the negative formation energy and the absence of imaginary modes in the phonon dispersion curve. Mechanical analysis indicates that Sr₂MnSbO₆ is mechanically stable, with significant anisotropy, mechanical strength, and ductility. Furthermore, the thermoelectric performance shows a high Seebeck coefficient and favorable power factor, underscoring its promising potential for high-efficiency energy conversion devices. These findings not only validate Sr₂MnSbO₆ as a stable material but also highlight its groundbreaking potential in next-generation spintronic and thermoelectric technologies.