Theoretical study on thermoelectric properties of Mg2Si and comparison to experiments

Mg2Si has been regarded as a potential candidate for thermoelectric applications in middle-temperature range (500-900 K). In order to better understand the temperature, doping level and composition dependent thermoelectric properties, we performed simulations that are based on the semi-classical electronic transport theory and the empirical lattice thermal conductivity model. The temperature and doping level dependence of the calculated Seebeck coefficients and electrical conductivity agree qualitatively with the previous experiments. By considering the influence of the chemical composition on the lattice thermal conductivity, we further estimated the thermoelectric figure-of-merit (ZT) for the Sb-doped Mg2Si samples. The results reproduced the temperature variation trends of the ZT values in the literature. The current work represents an attempt to combine the first-principles tools and the empirical models to evaluate the TE properties of the Mg2Si materials. It may shed some light on developing Mg2Si-based thermoelectric devices in the future. (C) 2012 Elsevier B. V. All rights reserved.