Tunneling spectroscopy of disordered two-dimensional electron gas in the quantum Hall regime

The tunneling density of states (TDOS) into a disordered two-dimensional electron gas is calculated in the quantum Hall regime, including electron-electron interactions. Combining general arguments and a detailed Hartree-Fock calculation, it is demonstrated that the quenching of the kinetic energy by the applied magnetic field leads to several universal features, nearly independent of the disorder potential, corresponding to the addition and removal spectrum in the valleys and tips of the disorder potential. These features are manifested as "sashes" in the TDOS spectra, and are in quantitative agreement with recent measurements. It is predicted that more such features will become observable with decreasing potential fluctuations.