TIME-REVERSAL SYMMETRY-BREAKING SURFACE-STATES IN T-J MODEL

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.