Pinhole junctions in d-wave superconductors

We present a self consistent treatment of pinhole junctions in d(x2-y2) superconductors. The current-phase relation j(s)(chi) is studied at different temperatures and at different angles alpha between the crystal (a) over cap-axis and the junction (surface) normal. We show that the critical current of a junction can be reduced by pair-breaking effects at the separation. We also study the Josephson energy of a pinhole as a function of the phase difference across the junction. In particular are mapped the positions of the energy minima X-min at different temperatures as functions of (alpha(L), alpha(R)), the crystal orientations of the left and right superconductors. With decreasing temperature there is an increasing range of crystal orientations where chi(min) varies continuously from 0 to pi. (C) 1998 Elsevier Science B.V.