Time Reversal Symmetry Breaking and Spontaneous Currents in s-Wave / Normal Metal / d-Wave Superconductor Sandwiches

Abstract

We study the physical properties of an $s$-wave -- normal metal -- $d$-wave junction in terms of the Andreev bound states in the normal metal layer. The phase dependence of bound states with different orientations leads to superconducting states with broken time reversal symmetry for generic orientations of the $d$-wave superconductor crystal. The occurrence of such a state and the associated spontaneous supercurrent along the junction is analyzed in the framework of Ginzburg-Landau theory and by the solution of the Bogolyubov-de Gennes equations.