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Engineering spin propagation across a hybrid organic/inorganic interface using a polar layer

Nature Materials volume 10, pages 39–44 (2011)Cite this article

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An Erratum to this article was published on 21 February 2011

This article has been updated

Abstract

Spintronics has shown a remarkable and rapid development, for example from the initial discovery of giant magnetoresistance in spin valves1 to their ubiquity in hard-disk read heads in a relatively short time. However, the ability to fully harness electron spin as another degree of freedom in semiconductor devices has been slower to take off. One future avenue that may expand the spintronic technology base is to take advantage of the flexibility intrinsic to organic semiconductors (OSCs), where it is possible to engineer and control their electronic properties and tailor them to obtain new device concepts2. Here we show that we can control the spin polarization of extracted charge carriers from an OSC by the inclusion of a thin interfacial layer of polar material. The electric dipole moment brought about by this layer shifts the OSC highest occupied molecular orbital with respect to the Fermi energy of the ferromagnetic contact. This approach allows us full control of the spin band appropriate for charge-carrier extraction, opening up new spintronic device concepts for future exploitation.

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Figure 1: A schematic of the device structure.
Figure 2: Spin-polarized charge carriers are present in the OSC, close to the top NiFe interface.
Figure 3: A comparison of the device magnetoresistance and spin polarization close to the top interface.
Figure 4: Schematic of hole transport in the OSC and how a vacuum level shift leads to a change of extracted spin polarization.

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Change history

  • 18 January 2011

    In the version of this Letter originally published, in the paragraph above the Methods section, 'kiloteslas' should have read 'kBT'. This has been corrected in the HTML and PDF versions.

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Acknowledgements

A.J.D. acknowledges financial support from the Royal Society, Leverhulme Trust and the EPSRC (grant EP/G054568/1), C.B. from the SNF (grant 200020-119784 and 200020-129484) and the NCCR program MaNEP and N.A.M. from the British Council. This experimental work was partly carried out at the Swiss Muon Source SμS.

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Authors and Affiliations

  1. Department of Physics and Fribourg Center for Nanomaterials, University of Fribourg, Chemin du Musée 3, CH-1700 Fribourg, Switzerland

    L. Schulz, V. K. Malik, C. Bernhard & A. J. Drew

  2. Queen Mary University of London, School of Physics, Mile End Road, London E1 4NS, UK

    L. Nuccio, M. Willis, P. Desai, P. Shakya, T. Kreouzis, W. P. Gillin & A. J. Drew

  3. ISIS Pulsed Neutron and Muon Source, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX, UK

    F. L. Pratt

  4. Department of Materials Science and Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, UK

    N. A. Morley

  5. Laboratory for Muon-Spin Spectroscopy, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland

    A. Suter, G. J. Nieuwenhuys, T. Prokscha & E. Morenzoni

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Contributions

A.J.D. was responsible for project planning and concept. L.S., L.N., M.W., V.K.M., C.B., F.L.P., N.A.M., A.S., G.J.N., T.P., E.M. and A.J.D. were responsible for the experimental measurements. L.S., L.N., W.P.G. and A.J.D. were responsible for the analysis and interpretation of results. P.D., P.S., T.K., W.P.G. and A.J.D. were responsible for the sample growth and characterization.

Corresponding authors

Correspondence to W. P. Gillin or A. J. Drew.

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The authors declare no competing financial interests.

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Schulz, L., Nuccio, L., Willis, M. et al. Engineering spin propagation across a hybrid organic/inorganic interface using a polar layer. Nature Mater 10, 39–44 (2011). https://doi.org/10.1038/nmat2912

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