Diffusion thermopower of a $p-$type Si/Si$_{1-x}$Ge$_x$ heterostructure at zero magnetic field

Abstract

We calculate the diffusion thermopower of the degenerate two-dimensional hole gas in a $p-$type Si/Si$_{1-x}$Ge$_x$ lattice mismatched heterostructure at low temperatures and zero magnetic field. The effects of possible scatterings, e.g. remote impurity, alloy disorder, interface roughness, deformation potential, and random piezoelectric on the hole mobility and the diffusion thermopower are examined. Calculated results are well fitted to the experimental data recently reported. In addition, we predict a possibility for the diffusion thermopower to change its sign as the SiGe layer thickness changes, the effect has not been discussed yet.