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arXiv · 1801.01855

Supercurrent through a spin-split quasi-ballistic point contact in an InAs nanowire

J. C. Estrada Saldaña·R. Žitko·J. P. Cleuziou·E. J. H. Lee·V. Zannier·D. Ercolani·L. Sorba·R. Aguado·S. De Franceschi
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Abstract

We study the superconducting proximity effect in an InAs nanowire contacted by Ta-based superconducting electrodes. Using local bottom gates, we control the potential landscape along the nanowire, tuning its conductance to a quasi-ballistic regime. At high magnetic field ($B$), we observe approximately quantized conductance plateaus associated with the first two spin-polarized one-dimensional modes. For $B < 1$ T, the onset of superconductivity occurs in concomitance with the development of sizeable charge localization leading to a 0.7-type conductance anomaly. In this regime, the proximity supercurrent exhibits an unusual, non-monotonic $B$ dependence. We interpret this finding in terms of a competition between the Kondo effect, dominating near $B=0$, and the Zeeman effect, enforcing spin polarization and the emergence of a $\pi$ phase shift in the Josephson relation at higher $B$.

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J. C. Estrada Saldaña, R. Žitko, J. P. Cleuziou, E. J. H. Lee, V. Zannier, D. Ercolani, L. Sorba, R. Aguado, S. De Franceschi. 2018-01-05. Supercurrent through a spin-split quasi-ballistic point contact in an InAs nanowire. https://doi.org/10.1126/sciadv.aav1235

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