Special CMP Seminar: “Beyond Homes scaling: disorder, the Planckian bound and a new universality”

18 Jun 2025
Seminars and colloquia
Time
Venue
Lindemann Lecture Theatre
Martin Wood Complex, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU
Speaker(s)

Professor Peter Hirschfeld, University of Florida

Seminar series
CMP seminar
For more information contact

Prof Amalia Coldea

Abstract

Beginning with high- T_c cuprate materials, it has been observed that many superconductors exhibit so-called "Homes scaling", in which the zero-temperature superfluid density, ρ_s0, is proportional to the product of the normal-state dc conductivity and the superconducting transition temperature, σ_dc T_c. For conventional, s-wave superconductors, such scaling has been shown to be a natural consequence of elastic-scattering disorder, but  we show that when an analogous calculation is carried out for elastic scattering in d-wave superconductors, a stark contrast emerges, with ρ_s0∝(σ_dc T_c )^2 in the dirty limit, in apparent violation of Homes scaling.  Within a simple approximate Migdal-Eliashberg treatment of inelastic scattering, I show how Homes scaling is recovered. In addition, I a present a revised analysis where both axes of the original Homes scaling plot are normalized by the Drude plasma weight, ω_(p,D)^2, and argue that this represents a powerful new tool for classifying superconductors in terms of order parameter symmetry, as well as scattering strength and character.