Study of superfluid condensation in the cuprates by andreev reflections

摘要

A brief review is given of the advantages of andreev scattering in the study of unconventional superconductors such as the cuprates. The use of clean interfaces is made possible by the Point Contact method. andreev scattering is sensitive to the presence of nodes in the order parameter, which has allowed for an easy check of its symmetry in a large unmber of cuprates. NdCeCuO and LaSrCuO near optimum doping are two interesting exceptions to a d-wave symmetry. andreev scattering probles the coherence energy scale in the superconducting state, which has been found to be smaller than the single particle eitation energy gap in the underdoped regime. The implications of this rsult for current models of the pseudogap are discussed.