Thermoelectric Potential of OsAl₂ Chimney LadderCompound: a Theoretical Investigation

We report on the theoretical study of the structural and electronic properties of OsAl₂ compound belonging to chimney ladder (CLs) phases. We used the full potential linearized augmented plane wave (FP-LAPW) method based on the density functional theory (DFT). The Boltzmann semi-classical transport equations were employed to investigate the thermoelectric properties. The type-MoSi₂ structure was found to be the most favorable phase to crystallize OsAl₂. In addition, the gap between the valence and conduction bands was calculated to be about 0.358 eV, indicating thereby an indirect band gap semiconducting nature. The thermoelectric properties, such as Seebeck coefficient, electrical conductivity, power factor, thermal conductivity, and figure of merit, were also calculated as a function of chemical potential, for a large range of temperatures, starting from room temperature and ending at 900°K. Our results demonstrate high thermoelectric performance with an important merit factor value of about 0.90, which is close to unity, hence revealing that the investigated OsAl₂ material has a true potential for thermoelectric applications.