All-optical spin switching in neutral or charged magnetic quantum dots

Abstract

The spin dynamics in a single semiconductor quantum dot doped with a single Mn atom are analyzed. We consider a neutral and a negatively charged dot and in both cases we concentrate on the light hole-to-conduction band transition. Both electrons and light holes couple to the Mn spin via the strong exchange interaction. After the excitation by an ultra short laser pulse oscillatory spin dynamics take place, where electron or hole can flip their spin accompanied by a change of the Mn spin. The Mn spin dynamics can be controlled by excitation with additional pulses. Starting from a given initial state we demonstrate that the Mn spin can be flipped all-optically into a steady final state in both neutral or charged quantum dots.