Comparative Study of Electronic Structure and Thermoelectric Properties of SnSe for Pnma and Cmcm Phase

Abstract

The electronic structure and thermoelectric properties of SnSe have been studied according to first principles and semiclassical Boltzmann theory. The decrease of the density of states (DOS) for SnSe from Pnma to Cmcm phase is mainly due to the decrease of Sn p-states and Se p-states. The main Seebeck coefficient peaks are higher for Pnma than Cmcm phase. The peak values of S2σ/τ increase faster with carrier concentration and temperature for n- compared with p-doping, indicating that n-doping can greatly enhance the electrical transport properties for Pnma phase, whereas the peak values for n-doping are almost the same as with p-doping for the Cmcm phase. It is also found that n-doping in the SnSe compound may be more favorable for thermoelectric performance for Pnma phase.