Control of single spins in individual magnetic quantum dots

Abstract

AbstractThe optical properties of individual quantum dots doped with a single Mn atom and charged with a single carrier (electron or hole) are analyzed. Bias controlled single‐carrier charging combined with photo depletion is used to control the charge state of individual Mn‐doped quantum dots. The emission of the neutral, negatively charged and positively charged excitons coupled with a single magnetic atom are observed in the same quantum dot. The emission pattern of the charged excitons differs strongly from that of the neu‐tral excitons (single and biexciton). This difference reflects the fact that the Mn spin is very sensitive to the number of electrons and holes in both the excited and the ground states of the optical transitions. The spectrum of charged excitons in interaction with the Mn atom shows a rich pattern that can be attributed to a strong anisotropy of the hole–Mn exchange interaction This opens the way of storing information on a single carrier spin on a long time scale in the absence of external magnetic field. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)