Superconductivity in monolayer FeSe enhanced by quantum geometry

We formulate the superfluid weight in unconventional superconductors with k-dependent Cooper pair potentials based on the geometric properties of Bloch electrons. We apply the formula to a model of monolayer FeSe obtained by first-principles calculation. Our numerical calculations point to a significant enhancement of the Berezinskii-Kosterlitz-Thouless transition temperature due to the geometric contribution to the superfluid weight, which is not included in the Fermi liquid theory. The k dependence of the gap function also stabilizes the superconducting state. Our results reveal that the geometric properties of Bloch electrons play an essential role in superconducting materials and pave the way for clarifying hidden aspects of superconductivity from the viewpoint of quantum geometry.

Automated summary

In this study, we formulated the superfluid weight in unconventional superconductors with k-dependent Cooper pair potentials based on the geometric properties of Bloch electrons, and applied it to a model of monolayer FeSe obtained through first-principles calculation. Our numerical calculations revealed a significant enhancement of the Berezinskii-Kosterlitz-Thouless transition temperature due to the geometric contribution to the superfluid weight.