Probing electron-electron interaction in quantum Hall systems with scanning tunneling spectroscopy

Abstract

Using low-temperature scanning tunneling spectroscopy applied to the Cs-induced two-dimensional electron system (2DES) on p-type InSb(110), we probe electron-electron interaction effects in the quantum Hall regime. The 2DES is decoupled from p-doped bulk states and exhibits spreading resistance within the insulating quantum Hall phases. In quantitative agreement with calculations we find an exchange enhancement of the spin splitting. Moreover, we observe that both the spatially averaged as well as the local density of states feature a characteristic Coulomb gap at the Fermi level. These results show that electron-electron interaction effects can be probed down to a resolution below all relevant length scales.

supplementary movie in ancillary files

References in corpus (4)

• The Quantum Hall Transition in Real Space: From Localized to Extended States
• Localized Distributions of Quasi Two-Dimensional Electronic States near Defects Artificially Created at Graphite Surfaces in Magnetic Fields
• Quantum Hall effect at cleaved InSb surfaces and low-temperature annealing effect
• Local density of states in disordered two-dimensional electron gases at high magnetic field