Magnetotunneling in double-barrier heterostructures

We report measurements of the current-voltage characteristics of an asymmetric GaAs/AlxGa1-xAs double-barrier resonant-tunneling device in a magnetic field B parallel to the tunneling direction. In the resonant-tunneling regime the magnetic field induces weak steplike features in the I(V) curve and sawtooth oscillations in the I(B) curve that are periodic in inverse field. We explain these magnetotunneling features by Landau quantization of the three-dimensional states in the emitter and the two-dimensional states in the well, which induces steplike structure in the tunneling supply function. The experimental I(V,B) line shape is in good agreement with self-consistent numerical calculations.