Charge Imbalance Relaxation Due to Pair Breaking Perturbation by Magnetic Field

Abstract

We observed the relaxation of the charge imbalance of nonequilibrium superconductivity due to pair breaking perturbation by magnetic field. We performed an injection experiment using a multiterminal tunnel junction device fabricated by electron beam lithography. We observed that excess current due to charge imbalance was considerably suppressed by weak magnetic fields perpendicular to the substrate. The suppression tended to vanish as magnetic field was tilted. We analyzed the result using the Boltzmann transport theory of charge imbalance involving relaxation by pair breaking perturbation.