Universal suppression of superfluid weight by disorder independent of quantum geometry and band dispersion

TL;DR

This paper demonstrates that disorder universally suppresses superfluid weight regardless of quantum geometry or band flatness, indicating flat-band superconductors are as resilient to disorder as conventional ones.

Contribution

It reveals that the disorder-induced suppression of superfluid weight is universal and independent of quantum geometry and band dispersion, challenging previous assumptions.

Findings

Disorder suppresses superfluid weight universally across models.

Superfluid weight suppression is independent of quantum geometry.

Flat-band superconductors are as resilient to disorder as conventional superconductors.

Abstract

Motivated by the experimental progress in controlling the properties of the energy bands in superconductors, significant theoretical efforts have been devoted to study the effect of the quantum geometry and the flatness of the dispersion on the superfluid weight. In conventional superconductors, where the energy bands are wide and the Fermi energy is large, the contribution due to the quantum geometry is negligible, but in the opposite limit of flat-band superconductors the superfluid weight originates purely from the quantum geometry of Bloch wave functions. Here, we study how the energy band dispersion and the quantum geometry affect the disorder-induced suppression of the superfluid weight. Surprisingly, we find that the disorder-dependence of the superfluid weight is universal across a variety of models, and independent of the quantum geometry and the flatness of the dispersion. Our results suggest that a flat-band superconductor is as resilient to disorder as a conventional superconductor.