Dresden 2014 – wissenschaftliches Programm
O 68.3: Vortrag
Donnerstag, 3. April 2014, 10:30–10:45, POT 151
Indirect Excitons Spin manipulation in GaAs/AlxGa1−xAs double quantum wells — •Adriano Violante1, Snežana Lazić2, Klaus Biermann1, Rudolph Hey1, Paulo Santos1, Kobi Kohen3, and Ronen Rapaport3 — 1Paul-Drude-Institut für Festkörperelektronik, Berlin, Germany — 2Departamento de Física de Materiales, Universidad Autónoma de Madrid, Madrid, Spain — 3Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem, Israel
A spatially indirect exciton (IX) is a bound state of an electron and a hole localized in different quantum wells (QWs) of a double quantum well structure (DQW). In an IX, the spatial separation of electrons and holes reduces the exchange interaction, thus significantly enhancing the spin lifetime with respect to the direct QW excitons.  In this contribution, we show that spin-polarized IXs created using a circularly polarized laser beam diffuse up to distances 15 µm away from the generation point, revealing spatial oscillations of the polarization degree ρz. The latter are attributed to the precession of the spin vector in the spin-orbit effective magnetic field BSO as they move away from the excitation spot, which can be modulated both with electric and magnetic fields. The IXs spin transport using acoustic fields is also discussed.
 J. R. Leonard, Y. Y. Kuznetsova, S. Yang, L. V. Butov, T. Ostatnick, A. Kavokin, and A. C. Gossard. Nano Lett. 9, 4204-4208 (2009)