Time-reversal symmetry breaking surface states of d-wave superconductors induced by an additional order parameter with negative Tc
Abstract
Surface states of dx2-y2-wave superconductors are studied using the Ginzburg-Landau (GL) theory. For a [110] surface it has been known that the time-reversal symmetry (T) breaking surface state, (d+-is)-wave state, can occur if the bare transition temperature of the s-wave order parameter (OP) is positive. We show that even if this bare Tc is negative, it is possible to break T because the coupling to the spontaneously generated magnetic field may induce the s-wave OP. The T-breaking state is favored when the GL parameter (kappa) is small.
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