Seebeck effect in dilute two-dimensional electron systems: temperature dependencies of diffusion and phonon-drag thermoelectric powers

Considering screeening of electron scattering interactions in terms of the finite-temperature STLS theory and solving the linearized Boltzmann equation (with no appeal to a relaxation time approximation), we present a theoretical analysis of the low-temperature Seebeck effect in two-dimensional semiconductors with dilute electron densities. We find that the temperature ($T$) dependencies of the diffusion and phonon-drag thermoelectric powers ($S_d$ and $S_g$) can no longer be described by the conventional simple power-laws. As temperature increases, $\mathrm{\mid }{S}_d\mathrm{\mid }\mathrm{/}T$ decreases when $T\gtrsim 0.1 \epsilon_F$($\epsilon_F$istheFermienergy),while$|S_g|$ first increases and then falls, resulting a peak located at a temperature between Bloch-Gr"uneisen temperature and ${ϵ}_F$.