Nonlinear resonant tunneling in low-dimensional systems in a magnetic field: Energy dispersion

We study two-dimensional to two-dimensional (2D–2D) tunneling between two electron layers separated by a wide barrier in an in-plane magnetic field B. The electron gases are separately in equilibrium with their chemical potentials displaced by the bias energy V. We show for a general electronic structure that the tunneling current shows a “fish-like” domain shape on the Δk-V plane where Δk∝B is the B-induced wave number displacement. The domain shape is determined by the Fermi energies and wave numbers. The boundaries between the high-, low-, and zero-current regions are sharp, representing the high differential conductance and are made of a combination of regular, inverted, and shifted energy-dispersion curves. This result is also valid for 2D–1D and 1D–1D tunneling. The observed data for the 2D–2D tunneling currents as well as the differential conductance in GaAs/AlxGa1-xAs double quantum wells yield good agreement with the predicted domain shape.