Two-Channel Kondo Physics in a Majorana Island Coupled to a Josephson Junction

Abstract

We study a Majorana island coupled to a bulk superconductor via a Josephson junction and to multiple external normal leads. In the absence of the Josephson coupling, the system displays a topological Kondo state, which had been largely studied recently. However, we find that this state is unstable even to small Josephson coupling, which instead leads at low temperature $T$ to a new fixed point. Most interesting is the case of three external leads, forming a minimal electronic realization of the long sought two-channel Kondo effect. While the $T=0$ conductance corresponds to simple resonant Andreev reflection, the leading $T$ dependence forms an experimental fingerprint for non-Fermi liquid properties.

10 pages, 7 figures

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Cited by in corpus (3)

• Topological Kondo Device for distinguishing Quasi-Majorana and Majorana signatures
• Strongly correlated electrons in superconducting islands with fluctuating Cooper pairs
• Relevance of Anisotropy in the Kondo Effect: Lessons From the Symplectic Case