Phase Fluctuations in High Temperature Superconductors

TL;DR

This paper investigates phase fluctuations in high-temperature superconductors using a combined XY model and Bogoliubov-de Gennes formalism, explaining inhomogeneities and impurity effects observed experimentally.

Contribution

It introduces a field-theoretical approach to incorporate phase fluctuations in the pseudogap state, linking inhomogeneous local order parameters with experimental observations.

Findings

Resonance peak evolves smoothly across $T_c$ with temperature increase.

Inhomogeneous local order parameters are characterized above $T_c$.

The model aligns with recent experimental data on impurity effects.

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.