Metastable Charge Distribution Between Degenerate Landau Levels

TL;DR

This paper investigates charge distribution stability in two-dimensional electron systems with crossing Landau levels, revealing hysteresis due to disorder and conditions for fractional quantum Hall states.

Contribution

It introduces the concept of metastable charge distributions between degenerate Landau levels in wide quantum wells with strong interactions and disorder effects.

Findings

Hysteresis observed in electron distribution at Landau level crossing

Multiple minima appear at fractional fillings 1/3 and 2/3

Fractional quantum Hall effect can be stabilized under certain conditions

Abstract

We study two dimensional electron systems confined in wide quantum wells whose subband separation is comparable with the Zeeman energy. Two N = 0 Landau levels from different subbands and with opposite spins are pinned in energy when they cross each other and electrons can freely transfer between them. When the disorder is strong, we observe clear hysteresis in our data corresponding to instability of the electron distribution in the two crossing levels. When the intra-layer interaction dominates, multiple minima appear when a Landau level is 1/3 or 2/3 filled and fractional quantum hall effect can be stabilized.