Berlin 2012 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 88: Quantum Dots and Wires: Transport Properties IV (mainly Double Dots and Point Contacts)
HL 88.7: Vortrag
Donnerstag, 29. März 2012, 18:00–18:15, EW 202
Large nuclear spin polarization in gate-defined quantum dots using a single-domain nanomagnet — •Gunnar Petersen1, Eric A. Hoffmann1, Dieter Schuh2, Werner Wegscheider2,3, and Stefan Ludwig1 — 1CeNS und Fakultät für Physik, Ludwig-Maximilians-Universität, München — 2Institut für Angewandte und Experimentelle Physik, Universität Regensburg — 3Solid State Physics Laboratory, ETH Zurich, Schweiz
Double quantum dots (QD) defined electrostatically in a two-dimensional electron system provide a versatile platform for investigating electron spin phenomena. In a GaAs based double QD system electrons are not completely isolated but weakly coupled to the host nuclei by hyperfine interaction. Such a coupling of electrons to a nuclear bath is common to a variety of material systems and gives rise to future applications in quantum information processing. For example, nuclear spins are a possible candidate for quantum memory1. Here we present experimental data demonstrating the manipulation of nuclear spins of the host material by hyperfine coupling to the electronic system. Nuclear polarization on the order of 50 percent is reached with the aid of a nanomagnet in the vicinity of the double QD. A phenomenological model is used to describe the dynamic build-up and decay of nuclear polarization. It provides a detailed understanding of the dynamic polarization process driven by electron-nuclear interaction.
[1] Morton, J. J. L. et al. Solid-state quantum memory using the (31)p nuclear spin. Nature 455, 1085-1088 (2008).