Broken time-reversal symmetry in Josephson junction involving two-band superconductorsT. K. Ng1 and N. Nagaosa2, 3
1 Department of Physics, Hong-Kong University of Science and Technology - Kawloon, Hong Kong, PRC
2 Department of Applied Physics, The University of Tokyo - 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
3 Cross Correlated Materials Research Group (CMRG), ASI, RIKEN - Wako 351-0198, Japan
received 2 April 2009; accepted in final form 17 June 2009; published July 2009
published online 17 July 2009
A novel time-reversal symmetry breaking state is found theoretically in the Josephson junction between a two-gap superconductor and a conventional s-wave superconductor. This occurs as a result of frustration between the three order parameters analogous to two antiferromagnetically coupled XY-spins put under a magnetic field. This leads to formation of interface states with energies inside the superconducting gap and modified flux quantization condition for a ring composed of the two types of superconductors.
74.20.De - Phenomenological theories (two-fluid, Ginzburg-Landau, etc.).
74.20.-z - Theories and models of superconducting state.
74.45.+c - Proximity effects; Andreev effect; SN and SNS junctions.
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