First-Principles Investigation of Structural, Thermoelectric, and Optical Properties of Half-Heusler Compound ScRhTe under Varied Pressure

Abstract

We thoroughly investigated the electronic structure and various properties of the half-Heusler compound ScRhTe using density functional theory calculations. The electronic structure shows that ScRhTe is a narrow-band-gap semiconductor. Owing to its characteristic conduction-band structure, ScRhTe has a higher Seebeck coefficient and a higher power factor for n-type doping than for p-type doping, with the maximum value of −493 µV K−1 appearing at 900 K. The optimal carrier concentration is approximately 5 × 1019 cm−3–1 × 1020 cm−3. In addition, ZTe is estimated as 0.95 at a doping level of approximately 1019 cm−3. Under pressure, the band structure changes from a direct to an indirect band gap, and the band gap increases as the pressure changes from tensile to compressive. The thermoelectric properties of ScRhTe improve under compressive pressure, whereas the optical properties improve greatly under tensile pressure. By varying the pressure, the electronic structure and various properties of ScRhTe can be effectively adjusted, which signifies that ScRhTe has the potential to become an important optoelectronic or thermoelectric material.