Chiral symmetry breaking and the Josephson current in a ballistic superconductor-quantum wire-superconductor junction
I.V. Krive1,2, L.Y. Gorelik1, R.I. Shekhter1, and M. Jonson1
1Department of Applied Physics, Chalmers University of Technology and Göteborg University SE-412 96 Göteborg, Sweden
2B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, 47 Lenin Ave., Kharkov 61103, Ukraine
Received November 7, 2003, revised December 15, 2003
We evaluate the Josephson current through a quasi-1D quantum wire coupled to bulk superconductors. It is shown that the interplay of Rashba spin–orbit interaction and Zeeman splitting results in the appearence of a Josephson current even in the absence of any phase difference between the superconductors. In a transparent junction (D ≃ 1) at low temperatures this anomalous supercurrent Jan appears abruptly for a Zeeman splitting of the order of the Andreev level spacing as the magnetic field is varied. In a low transparency (D << 1) junction one has Jan µ Ö D̅ under special (resonance) conditions. In the absence of Zeeman splitting the anomalous supercurrent disappears.
We have investigated the influence of dispersion asymmetry induced by the Rashba interaction in quasi-1D quantum wires on the critical Josephson current and have shown that the breakdown of chiral symmetry enhances the supercurrent.PACS: 74.80.Fp - 31.30.Gs - Hyperfine interactions and isotope effects, Jahn-Teller effect 71.70.Ej - Spin-orbit coupling, Zeeman and Stark splitting, Jahn-Teller effect 73.20.Dx -