76 research outputs found
Proximity effect with noncentrosymmetric superconductors
We describe the superconducting proximity effect taking place in a contact
between a noncentrosymmetric superconductor and a diffusive
normal/ferromagnetic metal within the quasiclassical theory of
superconductivity. By solving numerically the Usadel equation with boundary
conditions valid for arbitrary interface transparency, we show that the
analysis of the proximity-modified local density of states in the normal side
can be used to obtain information about the exotic superconductivity of
noncentrosymmetric materials. We point out the signatures of triplet pairing,
the coexistence of triplet and singlet pairing, and particular orbital
symmetries of the pair potential. Exploiting the directional dependence of the
spin polarization pair breaking effect on the triplet correlations, we show how
the order relation between triplet and singlet gaps can be discriminated and
that an estimation of the specific gap ratio is possible in some cases.Comment: 11 pages, 4 figure
Resonant generation of coherent phonons in a superconductor by ultrafast optical pump pulses
We study the generation of coherent phonons in a superconductor by ultrafast
optical pump pulses. The nonequilibrium dynamics of the coupled Bogoliubov
quasiparticle-phonon system after excitation with the pump pulse is analyzed by
means of the density-matrix formalism with the phonons treated at a full
quantum kinetic level. For ultrashort excitation pulses, the superconductor
exhibits a nonadiabatic behavior in which the superconducting order parameter
oscillates. We find that in this nonadiabatic regime the generation of coherent
phonons is resonantly enhanced when the frequency of the order-parameter
oscillation is tuned to the phonon energy, a condition that can be achieved in
experiments by varying the integrated pump pulse intensity.Comment: 8 pages, 4 figures, typos correcte
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