Thermopower in p-type GaAs/AlGaAs layers

We explain for the first time thermopower data for p-type GaAs/AlGaAs layers. The data span a temperature range between 0.2 to 1.2K. We calculate both the diffusion $S^d$ and the phonon-drag $S^g$ contributions to the thermopower. We find that $S^d$ is significant for temperatures up to 0.3K while at higher temperatures $S^g$ dominates. The calculated and measured $S^g$ agree very well with no adjustable parameters.