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arXiv · 0909.1213

Josephson effect for SU(4) carbon nanotube quantum dots

A. Zazunov·A. Levy Yeyati·R. Egger
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Abstract

We present the theory of the Josephson effect in nanotube dots where an SU(4) symmetry can be realized. We find a remarkably rich phase diagram that significantly differs from the SU(2) case. In particular, π-junction behavior is largely suppressed. We analytically obtain the Josephson current in various parameter regions: (i) in the Kondo regime, covering the full crossover from SU(4) to SU(2), (ii) for weak tunnel couplings, and (iii) for large BCS gap. The transition between these regions is studied numerically.

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A. Zazunov, A. Levy Yeyati, R. Egger. 2010-01-12. Josephson effect for SU(4) carbon nanotube quantum dots. https://doi.org/10.1103/physrevb.81.012502

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