Eur. Phys. J. B 22, 411-414 (2001)
https://doi.org/10.1007/PL00011150

Evidence for pseudogap and phase-coherence gap separation by Andreev reflection experiments in Au/La_2-xSr_xCuO₄ point-contact junctions

¹ INFM - Dipartimento di Fisica, Politecnico di Torino, 10129 Torino, Italy
² P.N. Lebedev Physical Institute, Russian Academy of Sciences, 117924 Moscow, Russia
³ Dipartimento di Chimica e Chimica Industriale, Universit di Genova, 16146 Genova, Italy

Corresponding author: ^a gonnelli@polito.it

Received: 14 June 2001
Published online: 15 August 2001

Abstract

We present new Au/La_2-xSr_xCuO₄ (LSCO) point-contact conductance measures as a function of voltage and temperature in samples with . Andreev reflection features disappear at about the bulk , giving no evidence of gap for . The fit of the normalized conductance at any supports a (s+d)-wave symmetry of the gap, whose dominant low-T s component follows the curve in contrast with recent angle-resolved photoemission spectroscopy and quasiparticle tunneling data. These results prove the separation between pseudogap and phase-coherence superconducting gap in LSCO at .