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Coherent spin transport through dynamic quantum dots

Nature Materials volume 4, pages 585588 (2005) | Download Citation

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Abstract

Spin transport and manipulation in semiconductors have been studied intensively with the ultimate goal of realizing spintronic devices. Previous work in GaAs has focused on controlling the carrier density1, crystallographic orientation2 and dimensionality3,4 to limit the electron spin decoherence and allow transport over long distances4,5,6,7. Here, we introduce a new method for the coherent transport of spin-polarized electronic wave packets using dynamic quantum dots (DQDs) created by the piezoelectric field of coherent acoustic phonons8,9,10,11. Photogenerated spin carriers transported by the DQDs in undoped GaAs (001) quantum wells exhibit a spin coherence length exceeding 100 μm, which is attributed to the simultaneous control of the carrier density and the dimensionality12 by the DQDs during transport. In the absence of an applied magnetic field, we observe the precession of the electron spin induced by the internal magnetic field associated with the spin splitting of the conduction band (Dresselhaus term)13. The coherent manipulation of the precession frequency is also achieved by applying an external magnetic field.

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Acknowledgements

We thank H. T. Grahn and G. S. Solomon for a critical reading of the manuscript and W. Seidel, S. Krauß and M. Höricke for technical support regarding sample fabrication. We would also like to thank the Bundesministerium für Bildung und Forschung for financial support. J.S. is personally grateful to the Alexander von Humboldt Foundation for financial support.

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Affiliations

  1. Paul-Drude-Institut für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin, Germany

    • James A. H. Stotz
    • , Rudolf Hey
    • , Paulo V. Santos
    •  & Klaus H. Ploog

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Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Paulo V. Santos.

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DOI

https://doi.org/10.1038/nmat1430

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