Electric and magnetic field manipulation and storage of charge-tunable excitons

Abstract

The excitonic spectrum of radially polarized semiconductor rings has been analyzed theoretically, in the presence of an in-plane electric field and a perpendicular magnetic field. Based on the numerically exact solution, a regime has been found where the exciton behaves as a single carrier or quasiparticle, with an effective and tunable electric charge determined by the ring geometry. A protocol is proposed for the storage of excitons without destroying them, consisting in converting them from “bright” to “dark,” by performing a sequence of well-defined steps. Accurate analytical approximations are provided for each of the exciton regimens found: quasifree, locked, and broken.