Unconventional superconductivity with a sign reversal in the order parameter of LaFeAsO1-xFx.
We argue that the newly discovered superconductivity in a nearly magnetic, Fe-based layered compound is unconventional and mediated by antiferromagnetic spin fluctuations, though different from the usual superexchange and specific to this compound. This resulting state is an example of extended s-wave pairing with a sign reversal of the order parameter between different Fermi surface sheets. The main role of doping in this scenario is to lower the density of states and suppress the pair-breaking ferromagnetic fluctuations.
Mazin
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Code 6393, Naval Research Laboratory, Washington, D.C. 20375, USA.
Singh
D J
DJ
Johannes
M D
MD
Du
M H
MH