Tuesday, April 30, 2013

1304.7667 (Falko Pientka et al.)

Magneto-Josephson effects and Majorana bound states in quantum wires    [PDF]

Falko Pientka, Liang Jiang, David Pekker, Jason Alicea, Gil Refael, Yuval Oreg, Felix von Oppen
A prominent signature of Majorana bound states is the exotic Josephson effects they produce, the classic example being a fractional Josephson current with 4\pi periodicity in the phase difference across the junction. Recent work established that topological insulator edges support a novel `magneto-Josephson effect', whereby a dissipationless current exhibits 4\pi-periodic dependence also on the relative orientation of the Zeeman fields in the two banks of the junction. Here, we explore the magneto-Josephson effect in junctions based on spin-orbit coupled quantum wires. In contrast to the topological insulator case, the periodicities of the magneto-Josephson effect no longer follow from an exact superconductor-magnetism duality of the Hamiltonian. We employ numerical calculations as well as analytical arguments to identify the domain configurations that display exotic Josephson physics for quantum-wire junctions, and elucidate the characteristic differences with the corresponding setups for topological insulators edges. To provide guidance to experiments, we also estimate the magnitude of the magneto-Josephson effects in realistic parameter regimes, and compare the Majorana-related contribution to the coexisting 2\pi-periodic effects emerging from non-Majorana states.
View original: http://arxiv.org/abs/1304.7667

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