XX–XY interface band mixing in GaAs/AlAs heterostructures

The in-plane dispersion of the XX,Y states in a GaAs/AlAs “double-barrier structure” is measured by varying the angle of an in-plane magnetic field. When XX,Y (1) states in the emitter AlAs layer tunnel into collector View the MathML source states, a characteristic dumbbell shape is observed for the bias shift of the resonant tunneling peak versus magnetic field angle, with the major axis along [110] or View the MathML source. This corresponds to an elliptical constant energy surface in the collector AlAs layer which is rotated by 45° with respect to the bulk Fermi surface. We explain the new symmetry by XX–XY interface band mixing which is closely analogous to the widely studied Γ–XZ mixing. Our results provide new insight into the microscopic origin of both types of mixing.