Mobility anisotropy of two-dimensional hole gases in (001)GaAs/Al_0.5Ga_0.5As heterostructures and the influence of uniaxial compression

摘要

Transport properties of 2D hole gases in (001)GaAs/Al_0.5Ga_0.5As heterostructures in the [110] and [110] directions have been investigated. In-plane uniaxial compression up to 5 kbar was applied in one or the other of the two directions, and measurements were performed in the temperature range l .4--60 K and in a magnetic field up to 6 T. Without uniaxial compression the mobility is largest in the [110] direction, the [ 110]: [110] mobilities ratio attaining its largest values at low temperatures and high carrier densities. Interface roughness scattering together with acoustic phonon scattering is suggested to be the underlying phenomenon. Under uniaxial compression the electrical resistance decreases in the direction parallel to the compression, and it increases in the direction perpendicular to the compression. This behaviour is found to be in qualitative agreement with recent band structure calculations.