5,002 research outputs found
Local density of states at polygonal boundaries of d-wave superconductors
Besides the well-known existence of Andreev bound states, the zero-energy
local density of states at the boundary of a d-wave superconductor strongly
depends on the boundary geometry itself. In this work, we examine the influence
of both a simple wedge-shaped boundary geometry and a more complicated
polygonal or faceted boundary structure on the local density of states. For a
wedge-shaped boundary geometry, we find oscillations of the zero-energy density
of states in the corner of the wedge, depending on the opening angle of the
wedge. Furthermore, we study the influence of a single Abrikosov vortex
situated near a boundary, which is of either macroscopic or microscopic
roughness.Comment: 10 pages, 11 figures; submitted to Phys. Rev.
Shadow on the wall cast by an Abrikosov vortex
At the surface of a d-wave superconductor, a zero-energy peak in the
quasiparticle spectrum can be observed. This peak appears due to Andreev bound
states and is maximal if the nodal direction of the d-wave pairing potential is
perpendicular to the boundary. We examine the effect of a single Abrikosov
vortex in front of a reflecting boundary on the zero-energy density of states.
We can clearly see a splitting of the low-energy peak and therefore a
suppression of the zero-energy density of states in a shadow-like region
extending from the vortex to the boundary. This effect is stable for different
models of the single Abrikosov vortex, for different mean free paths and also
for different distances between the vortex center and the boundary. This
observation promises to have also a substantial influence on the differential
conductance and the tunneling characteristics for low excitation energies.Comment: 5 pages, 5 figure
Anatomy of point-contact Andreev reflection spectroscopy from the experimental point of view (review)
We review application of point-contact Andreev-reflection spectroscopy to
study elemental superconductors, where theoretical conditions for the smallness
of the point-contact size with respect to the characteristic lengths in the
superconductor can be satisfied. We discuss existing theoretical models and
identify new issues that have to be solved, especially when applying this
method to investigate more complex superconductors. We will also demonstrate
that some aspects of point-contact Andreev-reflection spectroscopy still need
to be addressed even when investigating ordinary metals.Comment: 20 pages, 18 figs. V2: Ref.60 and footnote 3 are added, a number of
minor fixe
Andreev bound states and tunneling characteristics of a non-centrosymmetric superconductor
The tunneling characteristics of planar junctions between a normal metal and
a non-centrosymmetric superconductor like CePt3Si are examined. It is shown
that the superconducting phase with mixed parity can give rise to
characteristic zero-bias anomalies in certain junction directions. The origin
of these zero-bias anomalies are Andreev bound states at the interface. The
tunneling characteristics for different directions allow to test the structure
of the parity-mixed pairing state.Comment: 4 pages, 3 figure
NN potentials from inverse scattering in the J-matrix approach
An approximate inverse scattering method [7,8] has been used to construct
separable potentials with the Laguerre form factors. As an application, we
invert the phase shifts of proton-proton in the and
channels and neutron-proton in the channel elastic scattering. In
the latter case the deuteron wave function of a realistic potential was
used as input.Comment: LaTex2e, 17 pages, 3 Postscript figures; corrected typo
Josephson effect in superconducting constrictions with hybrid SF electrodes: peculiar properties determined by the misorientation of magnetizations
Josephson current in SFcFS junctions with arbitrary transparency of the
constriction (c) is investigated. The emphasis is done on the analysis of the
supercurrent dependencies on the misorientation angle between the
in-plane magnetizations of diffusive ferromagnetic layers (F). It is found that
the current-phase relation may be radically modified with the variation: the harmonic vanishes for definite value of
provided for identical orientation of the magnetizations () the junction is in the state. The Josephson current may exhibit a
nonmonotonic dependence on the misorientation angle both for realization of and state at . We also analyze the effect of exchange
field induced enhancement of the critical current which may occur in definite
range of .Comment: 7 pages, 5 figures, submitted to JETP Letter
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