The fundamental flaw of almost all microscopic theories of superconductivity

When a type I simply connected superconducting body in the presence of an external magnetic field transits into the normal state, magnetic field lines start to penetrate the body, and Faraday’s law induces electric currents opposing the change in magnetic flux. Those currents have to die down without generation of entropy to preserve the reversibility of the process, necessitated by the existence of the Meissner effect. How electric currents die down without entropy generation cannot be explained by conventional BCS theory nor by any of the other existing microscopic theories of superconductivity except for the theory of hole superconductivity. I will explain the microscopic reason why only materials with hole carriers can solve this conundrum [1,2,3,4,5], which explains why the vast majority of superconducting elements and compounds have positive Hall coefficient. This fundamental fact renders almost all microscopic theories of superconductivity, including the conventional theory. irrelevant to the description of real superconducting materials, and explains why the worldwide endeavor to find new superconducting materials guided by the principles exposed by those theories has met with huge costs and no successes.



[1] J. E. Hirsch, Phys. Lett. A 134, 451 (1989).

[2] J. E. Hirsch, EPL 114 57001 (2016).

[3] J. E. Hirsch, Oxide-based Materials and Devices VIII; 101051V (2017).

[4] J. E. Hirsch, Phys. Rev. B 95, 014503 (2017).

[5] J. E. Hirsch, Materials 17, 254 (2024).