High-magnetic-field thermopower in a layered superlattice

Abstract

The electron diffusion contribution to the thermoelectric power is calculated for a layered superlattice in a high magnetic field. The shape of the quantum oscillations is shown to depend significantly on the ratio of the temperature to the interlayer bandwidth ($W$) divided by Boltzmann's constant (${k}_{B}$). When the highest occupied Landau level is partially filled, the thermopower is linear in temperature at low temperatures and saturates to a constant value for temperatures approximately comparable to or larger than ${\mathrm{Wk}}_{B}^{\ensuremath{-}1}$. When the highest occupied Landau level is nearly filled, the thermopower occurs via activation to the adjacent higher level. The effect of electron localization is discussed. This study provides useful information about some of the important properties of layered superlattices, such as the carrier densities, the Fermi temperatures, the electronic structures in the superlattice direction, and the effect of carrier localization.