Exploring the Thermoelectric Potential of MgB₄: Electronic Band Structure, Transport Properties, and Defect Chemistry

The demand for efficient and lightweight thermoelectric materials has surged due to their applications in electronics, wearable technology, and the aerospace industry. Conventional materials contain heavy, rare, and/or toxic elements, making them unsustainable for the future. This work presents a study of MgB4, a material that has not been studied as a thermoelectric material. We use advanced computational chemistry techniques, combining electronic structure calculations, lattice dynamics, and full defect chemistry analysis, to predict the thermoelectric figure of merit, ZT, across a range of carrier concentrations and temperatures in the theoretical p-type and n-type systems. The study suggests that p-type MgB4 is comparable to previously discovered Mg-based thermoelectrics under high-temperature conditions with a ZT of 0.47 at 1200 K. We also show that Ba-alloying up to 10% is a possible route toward improving thermoelectric performance as it increases the ZT to 0.66.