Intrinsic phonon-limited charge carrier mobilities in thermoelectric SnSe*

Within past few years, tin selenide (SnSe) has attracted intense interest due to its remarkable thermoelectric potential for both n- and p-type crystals. In this work, the intrinsic phonon-limited electron/hole mobilities of SnSe are investigated using Boltzmann transport equation based on first-principles calculated electron-phonon interactions. We find that the electrons have much larger mobilities than the holes. The mode-specific analysis shows that the highest longitudinal optical phonons, rather than previously assumed acoustic phonons, dominate the scattering processes and consequently the mobilities in SnSe. At room temperature, the largest mean free paths of electrons and holes in SnSe are about 18 nm and 10 nm, respectively.