Phase Fluctuations in High Temperature Superconductors

Abstract

Within the phase fluctuation picture for the pseudogap state of a high-$T_c$ superconductor, we incorporate the phase fluctuations generated by the classical XY model with the Bogoliubov-de Gennes formalism utilizing a field-theoretical method. This picture delineates the inhomogeneous characteristics of local order parameters observed in high-$T_c$ superconductors above $T_c$. We also compute the local density of states near a non-magnetic impurity with a strong scattering potential. The resonance peak smoothly evolves as temperature increases through $T_c$ without showing any sudden broadening, which is consistent with recent experimental findings.

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