A calculation of the phonon-drag contribution to the thermopower of quasi-2D electrons coupled to 3D phonons. I. General theory

A calculation is made of the phonon-drag contribution S g to the thermopower of a quasi-2D electron gas coupled to 3D phonons. It is based on coupled Boltzmann equations for the electrons and the phonons. The equations are linearised and solved in a relaxation time approximation. A final formula for S g is developed for weak electron-phonon coupling which is the case of interest in the low-dimensionality systems currently under experimental investigation.