One and Two Phonon Assisted Transitions between Exciton Spin States in a Quantum Dot

Abstract

Interest in spin effects has been growing recently due to their possible applications in spin based electronics and as means of information storage in quantum computing. Consequently, relaxation and decoherence of confined spins are intensely researched. The case of an electron confined in a quantum dot (QD) has been thoroughly studied theoretically, including phonon-assisted processes [1, 2], while exciton spin has been experimentally investigated [3], but only some decay channels have been examined theoretically. Three relevant phonon-assisted processes have been identified so far. One is a transition to dark states due to carrier–phonon interactions and the spin–orbit coupling [4]. The other two include a transition between bright states [5] and a transition to dark states [6, 7] and are caused by the interplay of the Bir–Pikus Hamiltonian and the short-range exchange interaction. In this paper, we study the processes resulting from the interplay of the Bir–Pikus Hamiltonian and the short-range exchange interaction. Apart from