Quartet Formation at (100)/(110) Interfaces of d-Wave Superconductors

A. A. ALIGIA, A. P. KAMPF, AND J. MANNHART

PHYSICAL REVIEW LETTERS

AMER PHYSICAL SOC

Año: 2005 vol. 94 p. 1 - 4

0031-9007

Across a faceted (100)/(110) interface between two dx2-y2 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 strongly enhances their binding at the interface. As a consequence, we propose that electrons tunnel in quartets across an interface with a staggered sequence of 0- and -junction contacts. We connect this finding to the recently observed h/4e oscillations in bicrystalline (100)/(110) SQUIDs of cuprate superconductors.