Professor Jorge E. Hirsch
Department of Physics, UCSD

Explanation of the Meissner Effect and Prediction of a Spin Meissner Effect in Superconductors

Abstract:

When a metal is cooled into the superconducting state in the presence of a static external magnetic field, a surface current starts flowing spontaneously that creates a magnetic field equal and opposite to the applied magnetic field in the interior of the body (Meissner effect). What is the force that generates this surface current, and how can it overcome Faraday's electric force that opposes it? How is angular momentum conserved? I argue that the conventional BCS-London theory of superconductivity cannot answer these questions.

I propose an explanation of the Meissner effect that requires new electrodynamic equations for superconductors, that are symmetric in electric and magnetic fields. These equations predict the existence of a spontaneous electric field in the interior of superconductors and the generation of a surface spin current when a metal is cooled into the superconducting state in the presence or absence of an external magnetic field. I call this the "Spin Meissner Effect" and predict that it is a universal property of all superconductors. The speed of the carriers of the spin current is hbar/(4 x electron mass x London penetration depth).

I discuss the relation of this physics to the theory of `hole superconductivity', to what extent it is supported or contradicted by existing experiments, and how it furnishes criteria that can help find new higher temperature superconductors.