Universal Linear Density of States for Tunneling into the Two-Dimensional Electron Gas in a Magnetic field

H. B. Chan, P. I. Glicofridis, R. C. Ashoori, M. L. Melloch

Published 1997-02-11Version 1

A new technique permits high fidelity measurement of the tunneling density of states (TDOS) of the two-dimensional electron gas. The obtained TDOS contains no distortions arising from low 2D in-plane conductivity and includes the contribution from localized tunneling sites. In a perpendicular magnetic field, a pseudogap develops in the TDOS at the Fermi level. Improved sensitivity enables resolution of a linear dependence of the TDOS on energy near the Fermi energy. The slopes of this linear gap are strongly field dependent. The data are suggestive of a new model of the gap at low energies.