Dresden 2009 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 28: Focused Session: Spin Transport and Coherence in Emerging Materials

MA 28.5: Vortrag

Mittwoch, 25. März 2009, 16:45–17:00, HSZ 101

Spin resonance of electrons confined in low dimensional SiGe heterostructures — •Ferdinand Lipps, Fabio Pezzoli, Mathieu Stoffel, Armando Rastelli, Vladislav Kataev, Oliver G. Schmidt, and Bernd Büchner — IFW Dresden, D-01171 Dresden,

Different kind of SiGe quantum dots (Pyramids, Domes, Barns) were grown with MBE. Due to strain induced in the silicon a confinement of electrons is caused. We performed ESR measurements at 9.56GHz on those low dimensional SiGe heterostructures in order to study the coherence times and relaxational processes of the confined spins. Shape of the dots as well as variations in spacing between stacked layers of dots critically influence the induced strain in the Si. This directly reflects in the confinement of spins and therefore their coherence times determined with ESR. Illumination with light above and below the Si bandgap generates additional electron-hole pairs. We discuss the relationship between shape of dots and resulting spin coherence and relaxation times of the confined spins as measured by ESR.