  Across a faceted (100)/(110) interface between two d-wave-superconductors the
structure of the superconducting order parameter leads to an alternating sign
of the local Josephson coupling. Describing the Cooper pair motion along and
across the interface by a one-dimensional boson lattice model, we show that a
small attractive interaction between the bosons boosts boson binding at the
interface -- a phenomenon, which is intimately tied to the staggered sequence
of 0- and Pi-junction contacts along the interface. We connect this finding to
the recently observed h/4e oscillations in (100)/(110) SQUIDS of cuprate
superconductors.
