Coulomb barrier to tunneling between parallel two-dimensional electron systems

Tunneling between parallel two-dimensional electron gases in double quantum wells is examined at both zero and high perpendicular magnetic field. The measured I-V characteristics show the magnetic field qualitatively alters the tunneling density of states, creating both a wide gap at the Fermi level and a much broader density of final states than is present at zero field. We suggest the origin of these effects lies in the strong Coulomb correlations characteristic of Landau quantized two-dimensional systems.