DQMP - Informal Seminar - 04.07.2024 - 14:00 - Prof. Jorge E Hirsch

04.07.2024 14:00 – 15:00

Electron-Phonon Superconductivity versus Hole Superconductivity
Jorge E Hirsch, Department of Physics, University of California San Diego

The conventional London-BCS theory of superconductivity [1] and its extensions [2] say that the electron-phonon interaction is what causes superconductivity in many materials, the so-called conventional superconductors. They predict that light elements should give rise to high critical temperatures, which guides the current search for high temperature superconductors, e.g. in hydrides under pressure. I will discuss an alternative theory [3], [4] that says that it is the hole nature of charge carriers that gives rise to superconductivity in all superconducting materials, and that the electron-phonon interaction plays no role. The alternative theory has some elements in common with the conventional theory and many differences. Unlike the conventional theory, the alternative theory is falsifiable by any superconducting material that does not conform to it. Instead, any observation that would potentially falsify the conventional theory can be dismissed with the argument that the material is an “unconventional superconductor”. I will explain how hole carriers pair without phonons playing a role, and discuss novel and suprising properties of superconductors predicted by the alternative theory, for example that the charge distribution in the ground state of superconductors is macroscopically inhomogeneous. Most importantly, I will argue that the alternative theory explains the Meissner effect and that the conventional theory cannot [5]. I will discuss predictions of the theory that have been experimentally verified, predictions that have not yet been tested experimentally that would validate the theory if verified, and guidelines for the search for higher temperature superconducting materials arising from this theory.

[1] Theory of Superconductivity, Phys. Rev. 108, 1175 (1957).
[2] Eliashberg theory: A short review, Annals of Physics 417, 168102 (2020).
[3] Superconductivity begins with H, both properly understood and misunderstood: superconductivity basics rethought, World Scientific, 2020.
[4] Many references in https://jorge.physics.ucsd.edu/hole.html
[5] How Alfven's theorem explains the Meissner effect, Modern Physics Letters B 34, 2050300 (2020) and references therein.



Organized by : Prof. Van der Marel

Lieu

Bâtiment: Ecole de Physique

Auditoire Stückelberg

entrée libre