THEORY OF HOLE CONDUCTIVITY IN SEMICONDUCTOR SUPERLATTICES

Conductivity and diffusion coefficients of the holes in semiconductor superlattices are calculated within the Kubo formalism, taking into ac count interaction of holes with the delta-correlated disorder potentia l. An analytical approach using the strong difference between the heav y-hole (hh) and light-hole (lh) effective masses is applied in order t o describe hole states in the lowest miniband. It is shown that lh-hh mixing leads to a multichannel description of hole transport, and lh-l ike channel (which is characterized by the lh effective mass in the tu nneling exponent) is more important for superlattices with wider poten tial barriers at higher temperatures and hole concentrations. Calculat ed values of the diffusion coefficient are compared with the available experimental data.