Accueil du site > Vie du laboratoire > Congrès / Colloques / Conférences > Optical Properties of Individual Nanowires and Quantum Dots in High Magnetic Field, Septembre 2014 > Programme du workshop > Abstract : Magneto-optical properties of singly Mn-doped InAs/GaAs quantum dots


Abstract : Magneto-optical properties of singly Mn-doped InAs/GaAs quantum dots

Self-assembled semiconductor quantum dots (QDs) made of InGaAs in GaAs and doped by a single manganese (Mn) atom, a shallow acceptor in InGaAs material, provide the remarkable possibility to optically probe at the few-spin level the exchange interactions between the Mn 3d5 electrons, its bound hole, and the QD-confined carriers (electron or hole). In the last 5 years, they have been explored in great details, with the help of of an external magnetic field and by using high-resolution micro-photoluminescence of charge-tunable Mn-doped QDs. From these investigations we could infer a complete description of Mn-doped QDs with a simplified spin Hamiltonian which essentially includes the 2-particle exchange interactions and the spin-orbit interaction typical of such QDs. In this framework we could figure out experiment schemes aiming at the control of a single dopant spin. Singly Mn-doped QDs define indeed at low temperature a 2-level quantum system associated to the Mn+hole angular momentum |Jz=+1> or |Jz=-1>. We could demonstrate the resonant optical pumping of these |±1> spin states when a suitable longitudinal magnetic field is applied, opening the way toward the coherent manipulation of a single Mn dopant. More recently, we evidenced the optical coupling between two Mn dopants incorporated in the same QD. Such a 2Mn-doped QD was identified thanks to its specific signature in magneto-optical spectroscopy and, from a quantitative analysis, it was shown that both dopants experienced an effective ferromagnetic interaction of about 70 µeV mediated by a photo-created hole.

Olivier Krebs LPN, Marcoussis