145 research outputs found

### Interface effects in superconductor-nanotubes hybrid structures

The objective of the present paper is to investigate the proximity effect in
junctions of superconductors with carbon nanotubes. The method is the lattice
BdG equations within the Hubbard model. The proximity effect depends
sensitively on the connection giving the possibility to control the proximity
effect by performing simple geometrical changes in the hybrid systemComment: 12 pages, 19 figure

### Resonant propagation of fluxons in corner junctions with triplet pairing symmetry

We present the numerical solutions for the I-V characteristics, and describe
the motion of fluxons in a frustrated Josephson junction made of an
unconventional triplet superconductor and an s-wave superconductor. In the
inline geometry, and long length limit the moving integer fluxon interacts with
the bound fractional fluxon but is not able to change its position or polarity.
We observe different modes of multifluxon propagation. In the small length
limit the moving fluxon is a combination of the stable solutions that exist in
the static case and additional steps are introduced in the I-V diagram.Comment: 19 pages, 8 figure

### Tunneling conductance in normal metal - triplet superconductor junction

We calculate the tunneling conductance spectra of a normal metal / insulator
/ triplet superconductor from the reflection amplitudes using the
Blonder-Tinkham-Klapwijk (BTK) formula. For the triplet superconductor we
assume one special p-wave order parameter having line nodes and two two
dimensional $f$-wave order parameters with line nodes breaking the
time-reversal symmetry. Also we examine nodeless pairing potentials. The
tunneling peaks are due to the formation of bound states for each surface
orientation at discrete quasiparticles trajectory angles. The tunneling spectra
can be used to distinguish the possible candidate pairing states of the
superconductor Sr$_2$RuO$_4$.Comment: 4 pages with 3 figures, presented at the second Euroconference on
Vortex Matter in Superconductors, 15-25 September 2001, Crete, Greec

### Proximity effect in ferromagnet-superconductor hybrid structures: role of the pairing symmetry

The spatial variations of the pair amplitude, and the local density of states
in d-wave or s-wave superconductor-ferromagnet hybrid structures are calculated
self consistently using the Bogoliubov-deGennes formalism within the two
dimensional extended Hubbard model. We describe the proximity effect in
superconductor / ferromagnet (SF) bilayers, FSF trilayers, and interfaces
between a superconductor and a ferromagnetic domain wall. We investigate in
detail the role played by the pairing symmetry, the exchange field, interfacial
scattering and crossed Andreev reflection.Comment: 27 pages, 14 figure

### Tunneling current in triplet f-wave superconductors with horizontal lines of nodes

We calculate the tunneling conductance spectra of a
normal-metal/insulator/triplet superconductor using the
Blonder-Tinkham-Klapwijk (BTK) formulation. Possible states for the
superconductor are considered with horizontal lines of nodes, breaking the time
reversal symmetry. These results would be useful to discriminate between
pairing states in superonductor Sr$_2$RuO$_4$ and also in UPt$_3$.Comment: 12 pages, 7 figure

### Charge current in ferromagnet - triplet superconductor junctions

We calculate the tunneling conductance spectra of a ferromagnetic metal /
insulator / triplet superconductor from the reflection amplitudes using the
Blonder-Tinkham-Klapwijk (BTK) formula. For the triplet superconductor, we
assume one special $p$-wave order parameter, having line nodes, and two two
dimensional $f$-wave order parameters with line nodes, breaking the time
reversal symmetry. Also we examine nodeless pairing potentials. The evolution
of the spectra with the exchange potential depends solely on the topology of
the gap. The weak Andreev reflection within the ferromagnet results in the
suppression of the tunneling conductance and eliminates the resonances due to
the anisotropy of the pairing potential. The tunneling spectra splits
asymmetrically with respect to $E=0$ under the influence of an external
magnetic field. The results can be used to distinguish between the possible
candidate pairing states of the superconductor Sr$_2$RuO$_4$.Comment: 15 pages with 8 figure

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