Theory of hole conductivity in semiconductor superlattices.

Abstract

Conductivity and diffusion coefficients of the holes in semiconductor superlattices are calculated within the Kubo formalism, taking into account interaction of holes with the \ensuremath{\delta}-correlated disorder potential. An analytical approach using the strong difference between the heavy-hole (hh) and light-hole (lh) effective masses is applied in order to describe hole states in the lowest miniband. It is shown that lh-hh mixing leads to a multichannel description of hole transport, and lh-like channel (which is characterized by the lh effective mass in the tunneling exponent) is more important for superlattices with wider potential barriers at higher temperatures and hole concentrations. Calculated values of the diffusion coefficient are compared with the available experimental data.