New insulating phases of two-dimensional electrons in high Landau levels: observation of sharp thresholds to conduction

K. B. Cooper, M. P. Lilly, J. P. Eisenstein, L. N. Pfeiffer, K. W. West

Published 1999-07-23Version 1

The intriguing re-entrant integer quantized Hall states recently discovered in high Landau levels of high-mobility 2D electron systems are found to exhibit extremely non-linear transport. At small currents these states reflect insulating behavior of the electrons in the uppermost Landau level. At larger currents, however, a discontinuous and hysteretic transition to a conducting state is observed. These phenomena, found only in very narrow magnetic field ranges, are suggestive of the depinning of a charge density wave state, but other explanations can also be constructed.