Berlin 2015 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 41: Spintronics: Excitons and Local Spins (jointly with HL, MA)

TT 41.1: Vortrag

Dienstag, 17. März 2015, 09:30–09:45, ER 270

Transport and manipulation of indirect exciton spins in GaAs double quantum well structures — Adriano Violante, Serkan Büyükköse, Klaus Biermann, and •Paulo Santos — Paul-Drude-Institut für Festkörperelektronik, Berlin, Germany

Indirect excitons in double quantum well (DQW) structures are interesting particles for information storage due to the electrically controlled coupling to photons. Here, we report on the coherent control and transport of IX spins in GaAs DQWs using spatially and polarization resolved photoluminescence (PL). We show that optically IXs spins optically excited by a focused, circularly polarized light spot precess around the spin-orbit magnetic field while moving over distances exceeding 20 µm from the excitation spot. The spatial precession frequency depends on the spin transport direction and can be controlled by the bias applied across the DQW structure. From the dependence of the spin dynamics on transport direction, bias, and external magnetic fields we directly determined the Dresselhaus and Rashba electron spin splitting coefficients for the DQW structure. The long IX lifetimes, together with the negligible contribution of holes to the spin dynamics, are attributed to spatial separation of the electron and hole wave functions by the electric field, which reduces the electron-hole exchange interaction. If extended to the single exciton regime, the present results imply that IXs can be used as flying spin qubits for application in the quantum information processing.