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VOLUME 91 (2010) | ISSUE 8 |
PAGE 451
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Order parameter sign-reversal near -superconductor surface
A. M. Bobkov, I. V. Bobkova
Institute of Solid State Physics, 142432 Chernogolovka, Moscow reg., Russia
Abstract
The superconducting order parameter and LDOS spectra near an
impenetrable surface are studied
on the basis of selfconsistent calculations for a two band superconductor
with nodeless
extended s-wave order parameter symmetry, as possibly realized in
Fe-based high-temperature superconductors.
It is found that for a wide range of parameters the spatial behavior
of the order parameter at a surface
is not reduced to a trivial suppression. If the interband scattering
at a surface
is of the order of the intraband one or dominates it, it can be
energetically favorable to change the symmetry
of the superconducting state near the surface from to
conventional s-wave.
The range of existing of this surface conventional superconductivity
is very sensitive to the relative values of interband and intraband
pairing potentials. It is shown
that the LDOS spectra near the surface can qualitatively differ upon
calculating with and without
taking into account the selfconsistency of the order parameter.
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