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

Title : Piring enhanced by local orbital fluctuations in a model for monolayer FeSe

Authors: Changming Yue * and Philipp Werner †

Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland

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.

Link: https://journals.aps.org/prb/abstract/10.1103/PhysRevB.104.184507

PHYSICAL REVIEW B 104, 184507 (2021)

ACKNOWLEDGMENTS

The calculations were performed on the Beo05 cluster at the University of Fribourg, using a code based on iQIST. We acknowledge support from SNSF Grant No. 200021-196966.