MEASUREMENT OF THE KNIGHT FIELD AND LOCAL NUCLEAR DIPOLE-DIPOLE FIELD IN AN INGAAS/GAAS QUANTUM DOT ENSEMBLE

T. Auer, R. Oulton, A. Bauschulte, D.R. Yakovlev, M. Bayer, S.Yu. Verbin, R.V. Cherbunin, D. Reuter, A.D. Wieck

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Abstract

We present a comprehensive investigation of the electron-nuclear system of negatively charged InGaAs/GaAs self-assembled quantum dots (QDs) under the influence of weak external magnetic fields (up to 3 mT). We demonstrate that, in contrast to conventional semiconductor systems, these small fields have a profound influence on the electron spin dynamics, via the hyperfine interaction. QDs, with their comparatively limited number of nuclei, present electron-nuclear behavior that is unique to low-dimensional systems. We show that the conventional Hanle effect used to measure electron-spin relaxation times, for example, cannot be used in these systems when the spin lifetimes are long. An individual nucleus in the QD is subject to milli-Tesla effective fields, arising from the interaction with its nearest neighbors and with the electronic Knight field. The alignment of each nucleus is influenced by application of external fields of the same magnitude. A polarized nuclear system, which may have an effective field st
Original languageUndefined
Pages (from-to)205303_1-15
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume80
Issue number20
DOIs
StatePublished - 2009

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