Coulomb-Driven Destruction of Quantum Hall States in a Double Quantum Well

Abstract

Magnetotransport studies of double quantum well structures with interwell tunneling resolve the energy gap between the symmetric and antisymmetric electron states. The new quantum Hall states which originate from the symmetric/antisymmetric (SAS) energy gap are found to be missing in high perpendicular magnetic fields. Increasing barrier thickness between the two wells reduces the threshold magnetic field for the missing states. Recent calculations find that coulomb interactions drive the collapse of the SAS energy gap at high magnetic fields, in semi-quantitative agreement with experiment.