9,103 research outputs found
Nonmonotonic behavior of resistance in a superconductor-Luttinger liquid junction
Transport through a superconductor-Luttinger liquid junction is considered.
When the interaction in the Luttinger liquid is repulsive, the resistance of
the junction with a sufficiently clean interface shows nonmonotonic
temperature- or voltage-dependence due to the competition between the
superconductivity and the repulsive interaction. The result is discussed in
connection with recent experiments on single-wall carbon nanotubes in contact
with superconducting leads.Comment: Revtex4, 2 eps figure files, slightly revised from an earlier version
submitted to PRL on 2001.12.
Progressive evolution of tunneling characteristics of in-situ fabricated intrinsic Josephson junctions in Bi_2Sr_2CaCu_2O_{8+delta} single crystals
Stacks of a few intrinsic tunnel junctions were micro-fabricated on the
surface of Bi-2212 single crystals. The number of junctions in a stack was
tailored by progressively increasing the height of the stack by ion-beam
etching, while its tunneling characteristics were measured in-situ in a vacuum
chamber for temperatures down to ~13 K. Using this in-situ etching/measurements
technique in a single piece of crystal, we systematically excluded any spurious
effects arising from variations in the junction parameters and made clear
analysis on the following properties of the surface and inner conducting
planes. First, the tunneling resistance and the current-voltage curves are
scaled by the surface junction resistance. Second, we confirm that the
reduction in both the gap and the superconducting transition temperature of the
surface conducting plane in contact with a normal metal is not caused by the
variation in the doping level, but is caused by the proximity contact. Finally,
the main feature of a junction is not affected by the presence of other
junctions in a stack in a low bias region.Comment: 25 pages, 7 figures, submitted to Phys. Rev.
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