Transport properties of cubic crystalline Ge₂Sb₂Te₅: A potential low-temperature thermoelectric material

摘要

GeSbTe (GST) has been widely used as a popular phase change material. In this study, we show that it exhibits high Seebeck coefficients 200–300 μV/K in its cubic crystalline phase (c-GST) at remarkably high p-type doping levels of ∼1 × 10–6 × 10 cm at room temperature. More importantly, at low temperature (T = 200 K), the Seebeck coefficient was found to exceed 200 μV/K for a doping range of 1 × 10–3.5 × 10 cm. Given that the lattice thermal conductivity in this phase has already been measured to be extremely low (∼0.7 W/m-K at 300 K) [K. S. Siegert et al., Rep. Prog. Phys. 78, 013001 (2015)], our results suggest the possibility of using c-GST as a low-temperature thermoelectric material.