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arXiv · 1206.5844

Magnetic-field switchable metal-insulator transitions in a quasi-helical conductor

Bernd Braunecker·Anders Ström·G. I. Japaridze
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Abstract

We study Anderson localization in disordered helical conductors that are obtained from one-dimensional conductors with spin-orbit interaction and a magnetic field, or from equivalent systems. We call such conductors "quasi-helical" because the spins of the counterpropagating modes are not perfectly antiparallel and have a small spin-wavefunction overlap that is tunable by the magnetic field. Due to the overlap, disorder backscattering is possible and allows a localization transition. A conductor can pass through two localization transitions with increasing field, one from the conventionally localized system to the quasi-helical conductor (with localization length exceeding the system length), and one at a higher field again to a localized state, due now, however, to backscattering below the magnetic field induced pseudo-gap. We investigate these transitions using a unified two-step renormalization group approach.

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Bernd Braunecker, Anders Ström, G. I. Japaridze. 2013-03-02. Magnetic-field switchable metal-insulator transitions in a quasi-helical conductor. https://doi.org/10.1103/physrevb.87.075151

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