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arXiv · 0706.0792

Persistence of the 0.7 anomaly of quantum point contacts in high magnetic fields

E. J. Koop·A. I. Lerescu·J. Liu·B. J. van Wees·D. Reuter·A. D. Wieck·C. H. van der Wal
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Abstract

The spin degeneracy of the lowest subband that carries one-dimensional electron transport in quantum point contacts appears to be spontaneously lifted in zero magnetic field due to a phenomenon that is known as the 0.7 anomaly. We measured this energy splitting, and studied how it evolves into a splitting that is the sum of the Zeeman effect and a field-independent exchange contribution when applying a magnetic field. While this exchange contribution shows sample-to-sample fluctuations, it is for all QPCs correlated with the zero-field splitting of the 0.7 anomaly. This provides evidence that the splitting of the 0.7 anomaly is dominated by this field-independent exchange splitting.

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E. J. Koop, A. I. Lerescu, J. Liu, B. J. van Wees, D. Reuter, A. D. Wieck, C. H. van der Wal. 2007-06-06. Persistence of the 0.7 anomaly of quantum point contacts in high magnetic fields. https://arxiv.org/abs/0706.0792

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