High-field magnetoresistance in GaAs/Ga0.7Al0.3As heterojunctions arising from elastic and inelastic scattering

In this paper we present measurements and calculations that explain the high-field magnetoresistance observed up to 30 T in GaAs-${\mathrm{Ga}}_{\mathit{x}}$ ${\mathrm{Al}}_{1\mathrm{-}\mathit{x}}$As heterojunctions over the temperature range 1.5–300 K. The scattering mechanisms that determine the mobility analogue 1/${\mathit{n}}_{\mathit{e}}$e${\mathrm{\rho }}_{\mathit{x}\mathit{x}}$ are compared at B=0 and in high field, where it is found that the field and temperature dependence of the Landau-level broadening significantly influences the scattering. The calculations, based on the momentum balance equation, include all the scattering processes self-consistently in evaluation of both the density of states and resistivity. By this method we are able to obtain good agreement between experiment and theory, both at B=0 and in high magnetic field.