Optical control of the spin state of two Mn atoms in a quantum dot

We report on the optical spectroscopy of the spin of two magnetic atoms (Mn) embedded in an individual quantum dot interacting with a single electron, a single exciton, or a single trion. As a result of their interaction to a common entity, the Mn spins become correlated. The dynamics of this process is probed by time-resolved spectroscopy, which permits us to determine an optical orientation time in the range of a few tens of nanoseconds. In addition, we show that the energy of the collective spin states of the two Mn atoms can be tuned through the optical Stark effect induced by a resonant laser field.

This work is supported by the French ANR Contract QuAMOS, the Fondation Nanoscience (RTRA Grenoble), and the EU ITN Project Spin-Optronics. J.F.R. acknowledges funding from Ministerio de Economia, Grants No. FIS2010-21883-C02-01, Plan Nacional de I+D, codigo FIS No. FIS2010-21883-C02-01, and CONSOLIDER No. CSD2007-0010, and from Generalitat Valenciana, Grant Prometeo 2012-011.