Spin-lattice relaxation of an individual Mn2+ ion in a CdTe/ZnTe quantum dot

We present the study of the spin-lattice relaxation of an isolated Mn2+ ion in a single CdTe/ZnTe quantum dot. The measurements are done in a wide range of magnetic field. The spin-lattice relaxation rate is determined in a time resolved experiment. The ion spin state is driven out of equilibrium using optical orientation of the Mn2+ spin in a system of two coupled dots. Then the light is switched off and the Mn2+ ion spin relaxes. The Mn2+ spin state is measured after switching the light on again. We discuss the magnetic field dependence of the spin-relaxation rate in light of two theoretical models: one based on scattering of transverse acoustic phonons in the presence of a finite uniaxial Mn2+ spin anisotropy, and the second relying on presence of quantum dot charge state fluctuations.