Topological Phase Diagram of a Two-Subband Electron System

Abstract

We present a phase diagram for a two-dimensional electron system with two populated subbands. Using a gated GaAs/AlGaAs single quantum well, we have mapped out the phases of various quantum Hall states in the density-magnetic filed plane. The experimental phase diagram shows a very different topology from the conventional Landau fan diagram. We find regions of negative differential Hall resistance which are interpreted as preliminary evidence of the long sought reentrant quantum Hall transitions. We discuss the origins of the anomalous topology and the negative differential Hall resistance in terms of the Landau level and subband mixing.

4 pages, 4 figures

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Cited by in corpus (7)

• Magnetic Response Functions in Landau Levels
• Multiple Phases with the Same Quantized Hall Conductance in a Two-Subband System
• Landau Level Anticrossing Manifestations in the Phase Diagram Topology of a Two Subband System
• Landau Level Crossings and Extended-State Mapping in Magnetic Two-dimensional Electron Gases
• Unconventional Reentrant Quantum Hall Effect in a HgTe/CdHgTe Double Quantum Well
• Observation of an in-plane magnetic-field-driven phase transition in a quantum Hall system with SU(4) symmetry
• Nonlinear AC and DC Conductivities in a Two-Subband n-GaAs/AlAs Heterostructure