Tunneling spectroscopy of Landau levels at the edge of a quantum Hall system

The tunnel coupling between the edges of two-dimensional electron gases is investigated in the quantum Hall regime. At the overlaps of the edge dispersion curves originating from the two lateral quantum Hall systems, anticrossing takes place in the energy spectrum. The gaps give rise to peaks in the conductance that are periodic with the inverse magnetic field. With increasing bias voltage applied across the weak link, the gaps move along the dispersion curves higher or lower in energy for carrier injection from the anode or the cathode, respectively. The shift can hence be used to map the dispersion curves. In addition, the peaks split because of a nonuniform variation of the gap energies arising from different Landau levels.