K. Kuboki et M. Sigrist, TIME-REVERSAL SYMMETRY-BREAKING SURFACE-STATES IN T-J MODEL, Journal of the Physical Society of Japan, 67(8), 1998, pp. 2873-2880
Recently a phenomenological Ginzburg-Landau (GL) theory has been propo
sed to describe the occurrence of a locally time-reversal symmetry (T)
breaking state near a Josephson junction between unconventional super
conductors. In this paper we derive this type of GL free energy micros
copically from the t - J model within a slave-boson mean-field approxi
mation. The resulting GL free energy is shown to satisfy the condition
s to have a T-violating surface state. The existence of this junction
state may explain some of the recent experiments on High-T-c supercond
uctors.