Optical manipulation of a single Mn spin in a CdTe quantum dot

In this paper we demonstrate optical writing of information on the spin state of a single Mn ion embedded in a CdTe/ZnTe quantum dot. As a tool for Mn spin orientation we use a spin-conserving transfer of excitation between two coupled quantum dots, one of them containing the Mn ion. Excitons created by circularly polarized light act on the Mn ion via the sp-d exchange interaction and orient its spin. The magnetic field of 1 T strongly enhances the orientation efficiency due to suppression of fast Mn spin relaxation mechanisms. Dynamics of the Mn spin under polarized excitation was measured in a time-resolved experiment, in which the intensity and polarization of excitation were modulated. Observed dynamics of the Mn spin can be described with a simple rate equation model.