Nonlinear electromagnetic rectification of BCS-paired electrons at a superconductor surface

Abstract

A theory describing nonlinear electromagnetic rectification of BCS-paired electrons at a superconductor-vacuum interface by means of a monochromatic, plane electromagnetic wave incident at an oblique angle is presented. On the basis of a recently constructed nonlinear-response tensor, the forced nonlinear dc-current density is analyzed. A fundamental integro-differential equation incorporating the Meissner screening of the nonlinear response is established, and the prevailing dc-current density and the associated magnetostatic field are determined assuming the BCS-paired electrons to be specularly reflected from the surface. A self-consistency requirement for the forced nonlinear current density which has to be obeyed for any specular-reflection model is derived, and polarization selection rules for the incident electromagnetic field are established. For temperatures above the transition temperature, the present theory describes nonlinear electromagnetic rectification in a collisionless unpaired jellium. In the final part of the present work, the possibilities of achieving nonlinear electromagnetic rectification using incident waves of frequencies around the plasma edge, i.e., far above the superconducting gap frequency, are investigated. It is predicted that polariton-plasmon and plasmon-plasmon interactions can give rise to optical rectification.

Source-reported materials — not catalogue approval

Similar papers