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arXiv · 0708.3373

Energy-level pinning and the 0.7 spin state in one dimension: GaAs quantum wires studied using finite-bias spectroscopy

A. C. Graham·D. L. Sawkey·M. Pepper·M. Y. Simmons·D. A. Ritchie
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Abstract

We study the effects of electron-electron interactions on the energy levels of GaAs quantum wires (QWs) using finite-bias spectroscopy. We probe the energy spectrum at zero magnetic field, and at crossings of opposite-spin-levels in high in-plane magnetic field B. Our results constitute direct evidence that spin-up (higher energy) levels pin to the chemical potential as they populate. We also show that spin-up and spin-down levels abruptly rearrange at the crossing in a manner resembling the magnetic phase transitions predicted to occur at crossings of Landau levels. This rearranging and pinning of subbands provides a phenomenological explanation for the 0.7 structure, a one-dimensional (1D) nanomagnetic state, and its high-B variants.

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A. C. Graham, D. L. Sawkey, M. Pepper, M. Y. Simmons, D. A. Ritchie. 2007-08-24. Energy-level pinning and the 0.7 spin state in one dimension: GaAs quantum wires studied using finite-bias spectroscopy. https://doi.org/10.1103/physrevb.75.035331

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