Issue
EPL
Volume 87, Number 1, July 2009
Article Number 17003
Number of page(s) 5
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
DOI http://dx.doi.org/10.1209/0295-5075/87/17003
Published online 17 July 2009
EPL, 87 (2009) 17003
DOI: 10.1209/0295-5075/87/17003

Broken time-reversal symmetry in Josephson junction involving two-band superconductors

T. 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

Abstract
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.

PACS
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.

© EPLA 2009