Modelling optical spin pumping of a single Mn atom in a CdTe quantum dot

We present a model for the incoherent spin dynamics of a Mn atom inside a CdTe quantum dot resonantly pumped by a laser light. The relevant quantum states of the system, 2S + 1 = 6 spin states in the optical ground state and the 24 = ( 2S + 1) * ( 2S(e) + 1) * (2S(h) + 1) are obtained from a effective spin Hamiltonian which describes the basic features of photoluminescence. The model includes the dominant Ising exchange interactions between the spins of the hole, the Mn and the electron but neglects coherent spin-flip terms. The Mn spin dynamics is described with a master equation for the populations of the 30 levels for which dissipative spin-flip processes are permitted. The optical spin pumping observed experimentally is explained if the Mn spin relaxation time in with (T-1X) exciton is much shorter than (T-1G), the Mn spin relaxation time without exciton.