Quantum Hall effect in spin-degenerate Landau levels: Spin-orbit enhancement of the conductivity

Abstract

The quantum Hall regime in a smooth random potential is considered when two disorder-broadened Zeeman levels overlap strongly. Spin-orbit coupling is found to cause a drastic change in the percolation network which leads to a strong enhancement of the dissipative conductivity at finite temperature, provided the Fermi level $E_F$ lies between the energies of two delocalized states $E=\pm \Delta$, $2\Delta$ being the Zeeman splitting. The conductivity is shown to exhibit a box-like behavior with changing magnetic field: ${\sigma }_{xx}$ is $\sim e^2/h$ at $|E_F|<\Delta$ and exponentially small otherwise. Two peaks of ${\sigma }_{xx}$ arising as $T\to 0$ are found to be strongly asymmetric.

4 pages, RevTeX 3.0, 3 uuencoded PostScript figures

References in corpus (2)

• A Unified Model for Two Localisation Problems: Electron States in Spin-Degenerate Landau Levels, and in a Random Magnetic Field
• Corrections to Scaling in the Integer Quantum Hall Effect

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• Spinful Aubry-Andre model in a magnetic field: Delocalization facilitated by a weak spin-orbit coupling
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