Pairing enhanced by local orbital fluctuations in a model for monolayer FeSe

TL;DR

This study uses dynamical mean field theory to explore how local orbital fluctuations influence pairing in monolayer FeSe, offering new insights into the mechanisms behind its superconductivity.

Contribution

It provides an alternative interpretation of superconductivity in FeSe monolayers emphasizing local orbital fluctuations, connecting spin/orbital freezing theory with nematic fluctuation studies.

Findings

Superconductivity linked to local orbital fluctuations and phase rigidity.

Phase diagram consistent with previous lattice Monte Carlo results.

Clarifies the relationship between superfluid stiffness and orbital fluctuations.

Abstract

The pairing mechanism in different classes of correlated materials, including iron based superconductors, is still under debate. For FeSe monolayers, uniform nematic fluctuations have been shown in a lattice Monte Carlo study to play a potentially important role. Here, using dynamical mean field theory calculations for the same model system, we obtain a similar phase diagram and provide an alternative interpretation of the superconductivity in terms of local orbital fluctuations and phase rigidity. Our study clarifies the relation between the superconducting order parameter, superfluid stiffness and orbital fluctuations, and provides a link between the spin/orbital freezing theory of unconventional superconductivity and theoretical works considering the role of nematic fluctuations.