Heuristic bounds on superconductivity and how to exceed them
Abstract
What limits the value of the superconducting transition temperature (Tc) is a question of great fundamental and practical importance. Various heuristic upper bounds on Tc have been proposed, expressed as fractions of the Fermi temperature, TF, the zero-temperature superfluid stiffness, ρs(0), or a characteristic Debye frequency, ω0. We show that while these bounds are physically motivated and are certainly useful in many relevant situations, none of them serve as a fundamental bound on Tc. To demonstrate this, we provide explicit models where Tc/TF (with an appropriately defined TF), Tc/ρs(0), and Tc/ω0 are unbounded.
- Publication:
-
npj Quantum Materials
- Pub Date:
- 2022
- DOI:
- 10.1038/s41535-022-00491-1
- arXiv:
- arXiv:2105.09322
- Bibcode:
- 2022npjQM...7...83H
- Keywords:
-
- Condensed Matter - Superconductivity;
- Condensed Matter - Strongly Correlated Electrons
- E-Print:
- 6 pages, 3 figures + appendices