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

Description

Motivated by the experimental progresses in controlling the properties of the energy bands in superconductors, using for instance moiré engineering, significant theoretical efforts have been devoted to study the effect of the quantum geometry and the flatness of the dispersion on the superfluid weight (superfluid density). 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 the Bloch wave functions.
In this work [7], 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 theoretical 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, even if the flat band is topologically nontrivial with nonzero Chern number.

Period	3 Mar 2022
Event title	Physics Days: Annual Meeting of the Finnish Physical Society
Event type	Conference
Location	Espoo, FinlandShow on map
Degree of Recognition	National