Photocarrier-induced spin heating and spin-lattice relaxation in diluted magnetic Stranski-Krastanov quantum dots

Abstract

Using the photoluminescence as a monitor, the Mn spin heating via photoexcited carriers and the spin-lattice relaxation of the magnetic ions in (Cd,Mn)Se quantum dots are studied. Spin dissipation times in the $1\phantom{\rule{0.3em}{0ex}}\ensuremath{\mu}\mathrm{s}$ range are observed. Direct heating via spin exchange with the photocarriers plays a minor role. The dependence of the spin-lattice relaxation rate on Mn concentration, temperature, as well as magnetic field indicates that an Orbach process (in a locally heated environment) via Mn pairs is responsible for the dissipation of the magnetic ion spin.