Proximity-induced time-reversal symmetry breaking at Josephson junctions between unconventional superconductors

It is shown that a locally time-reversal symmetry breaking state can occur at Josephson junctions between unconventional superconductors due to the angular structure of their pair wave function. The origin is the order parameter induced by the proximity effect at the junction, which can combine with the bulk order parameter with a nontrivial relative phase. Experimental consequences of this effect in high-temperature superconductors are examined.