INFLUENCE OF QUANTUM-INTERFERENCE EFFECTS ON HOLE MOBILITY IN SUPERLATTICES

The influence of quantum interference (weak localization) on perpendicular transport of holes in superlattices is investigated. Due to heavy-hole effective mass, the miniband width is small and the collisional broadening Gamma can be larger than the Fermi energy epsilon(F). In such situations, the quasiparticle approximation breaks down and the particle-particle diffusion propagator (from coherent backscattering) contains the effective diffusion coefficient ($) over tilde D-Z, which significantly differs from the classical one. In this case the Einstein relation between the effective diffusion constant and the conductivity is not valid. The correction to the conductivity caused by quantum interference is not small and leads to a large reduction in hole mobility. Numerical calculations of the hole mobility versus superlattice period and temperature are in good agreement with experimental results and show a significant deviation from previous theories.