Enhanced thermopower in rock-salt SnTe–CdTe from band convergence

Abstract

SnCd_xTe materials were synthesized by the zone-melting method for this thermoelectric performance study. The X-ray diffraction results show that the lattice parameter decreases with increasing x, following Vegard's law of rock-salt structure SnTe and CdTe. Besides, the room temperature Seebeck coefficients of the SnCd_xTe system are enhanced to >60 μV K⁻¹, larger than those of Cd-doped SnTe synthesized by spark plasma sintering. A large power factor of ∼25 μW cm⁻¹ K⁻¹ is achieved in SnCd_0.12Te at 820 K, which rivals those of high performance PbTe-based materials. As a result, the highest ZT of ∼1.03 at 820 K was achieved for SnCd_0.12Te.