SKM 2023 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 63: Superconductivity: Theory
TT 63.2: Talk
Friday, March 31, 2023, 09:45–10:00, HSZ 103
Universal suppression of superfluid weight by non-magnetic disorder in s -wave superconductors independent of quantum geometry and band dispersion — •Alexander Lau1, Sebastiano Peotta2, Dmitry I. Pikulin3, Enrico Rossi4, and Timo Hyart1, 2 — 1MagTop, IF PAN, Warsaw, Poland — 2Aalto University, Finland — 3Microsoft Quantum, Redmond, USA — 4William & Mary, Williamsburg, USA
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 quan-
tum 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 [1]. In particular, we consider non-magnetic disorder and s -wave superconductivity.
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.
[1] SciPost Phys. 13, 086 (2022)