https://doi.org/10.1007/PL00011150
Evidence for pseudogap and phase-coherence gap separation by Andreev reflection experiments in Au/La2-xSrxCuO4 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
We present new Au/La2-xSrxCuO4 (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 
.
PACS: 74.50.+r – Proximity effects; weak links; tunneling phenomena and Josephson effects / 74.25.Dw – Superconductivity phase diagrams / 74.72.Dn – La-based cuprates
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2001
