We made point-contact measurements with Au tips on La_{2-x}Sr_{x}CuO_{4} samples with 0.08 < x < 0.20 to investigate the relationship between superconducting gap and pseudogap. We obtained junctions whose conductance curves presented typical Andreev reflection features at all temperatures from 4.2 K up to T_c^A close to the bulk T_c. Their fit with the BTK-Tanaka-Kashiwaya model gives good results if a (s+d)-wave gap symmetry is used. The doping dependence of the low temperature dominant isotropic gap component Delta_{s} follows very well the T_{c} vs. x curve. These results support the separation between the superconducting (Andreev) gap and the pseudogap measured by angle-resolved photoemission spectroscopy (ARPES) and tunneling.
@article{arxiv.cond-mat/0107289,
title = {Andreev reflection in Au/La_{2-x}Sr_{x}CuO_{4} point-contact junctions: separation between pseudogap and phase-coherence gap},
author = {R. S. Gonnelli and A. Calzolari and D. Daghero and L. Natale and G. A. Ummarino and V. A. Stepanov and M. Ferretti},
journal= {arXiv preprint arXiv:cond-mat/0107289},
year = {2015}
}