Electron-hole dichotomy and enhancement of thermoelectric power factor by electron-hole-asymmetric relaxation time: a model study on a two-valley system with strong intervalley scattering

The role of electron-phonon scattering in thermoelectric transport has been paid much attention, especially in multivalley systems. By investigating a two-valley model with electron-phonon coupling, we find three electron transport regimes realized by electron-hole asymmetry of electron relaxation time due to the strong intervalley scattering. Seebeck coefficient denotes an electron-hole dichotomy due to this asymmetry. Also, the strong intervalley scattering can enhance power factor. Our finding sheds light on unexplored thermoelectric transport under the strong electron-phonon scattering.