Insulating Phases Induced by Crossing of Partially Filled Landau Levels in a Si Quantum Well

TL;DR

This paper investigates how crossing Landau levels in a high mobility Si quantum well leads to insulating phases, revealing localization phenomena during Landau level coincidences through magnetotransport measurements.

Contribution

It provides experimental evidence of insulating phases induced by Landau level crossings in a Si quantum well, highlighting the role of pseudospin states and localization.

Findings

Pronounced resistivity dips at Landau level crossings.

Hall resistivity changes consistent with particle-hole symmetry.

Localization of electrons or holes at Landau level coincidences.

Abstract

We study magnetotransport in a high mobility Si two-dimensional electron system by in situ tilting of the sample relative to the magnetic field. A pronounced dip in the longitudinal resistivity is observed during the Landau level crossing process for noninteger filling factors. Together with a Hall resistivity change which exhibits the particle-hole symmetry, this indicates that electrons or holes in the relevant Landau levels become localized at the coincidence where the pseudospin-unpolarized state is expected to be stable.