Issue |
Europhys. Lett.
Volume 58, Number 4, May 2002
|
|
---|---|---|
Page(s) | 589 - 595 | |
Section | Condensed matter: electronic structure, electrical, magnetic, and optical properties | |
DOI | https://doi.org/10.1209/epl/i2002-00436-6 | |
Published online | 01 May 2002 |
Absence of pseudogap in heavily overdoped
from tunneling spectroscopy of
break junctions
1
Materials Science Division, Argonne National
Laboratory - Argonne IL 60439, USA
2
Department of Physics, Izmir Institute of Technology -
TR-35437 Izmir, Turkey
3
Physics Division, Illinois Institute of Technology - Chicago
IL 60616, USA
4
Naval Research Laboratory - Washington DC 20375, USA
5
Department of Applied Physics, Science University of Tokyo -
Tokyo, Japan
Received:
29
September
2001
Accepted:
21
February
2002
We report tunneling spectroscopy of superconductor-insulator-superconductor
break junctions on heavily overdoped Bi2Sr2CaCu2O
with
K. At
, the junction conductances
display well-defined quasiparticle peaks at ±2Δ and in
some cases a Josephson current at zero bias. Gap values as small as
meV have been observed leading to 2
near
the BCS limit for
pairing. Temperature dependence
of the gap magnitude,
, follows the BCS relation and both
the quasiparticle gap and Josephson current vanish for
.
Above
, the tunneling conductance shows a flat background
without any indication of a pseudogap near the Fermi level.
PACS: 74.72.-h – High- compounds / 74.50.+r – Proximity effects, weak links, tunneling phenomena,
and Josephson effects / 74.62.Dh – Effects of crystal defects, doping and substitution
© EDP Sciences, 2002
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