Abstract

Single magnetic atoms, and assemblies of such atoms, on non-magnetic surfaces have recently attracted attention owing to their potential use in high-density magnetic data storage and as a platform for quantum computing1,2,3,4,5,6,7,8. A fundamental problem resulting from their quantum mechanical nature is that the localized magnetic moments of these atoms are easily destabilized by interactions with electrons, nuclear spins and lattice vibrations of the substrate3,4,5. Even when large magnetic fields are applied to stabilize the magnetic moment, the observed lifetimes remain rather short5,6 (less than a microsecond). Several routes for stabilizing the magnetic moment against fluctuations have been suggested, such as using thin insulating layers between the magnetic atom and the substrate to suppress the interactions with the substrate’s conduction electrons2,3,5, or coupling several magnetic moments together to reduce their quantum mechanical fluctuations7,8. Here we show that the magnetic moments of single holmium atoms on a highly conductive metallic substrate can reach lifetimes of the order of minutes. The necessary decoupling from the thermal bath of electrons, nuclear spins and lattice vibrations is achieved by a remarkable combination of several symmetries intrinsic to the system: time reversal symmetry, the internal symmetries of the total angular momentum and the point symmetry of the local environment of the magnetic atom.

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Acknowledgements

We acknowledge funding by the German Science Foundation (DFG) grant number Wu 349/4-2, the DFG priority programme SPP 1538 Spin Caloric Transport and the DFG Collaborative Research Centre SFB 762 Functionality of Oxide Interfaces. The calculations were performed at the Rechenzentrum Garching of the Max Planck Society.

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Affiliations

  1. Physikalisches Institut, Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Straße 1, 76131 Karlsruhe, Germany

    • Toshio Miyamachi
    • , Tobias Schuh
    • , Tobias Märkl
    • , Christopher Bresch
    • , Timofey Balashov
    • , Alexander Stöhr
    •  & Wulf Wulfhekel
  2. Institute of Solid State Physics, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwashi, Chiba 277-8581, Japan

    • Toshio Miyamachi
  3. Max-Planck-Institut für Festkörperforschung, Heisenbergstraße 1, 70569 Stuttgart, Germany

    • Alexander Stöhr
  4. Institut für Theoretische Festkörperphysik, Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Straße 1, 76131 Karlsruhe, Germany

    • Christian Karlewski
    • , Stephan André
    • , Michael Marthaler
    •  & Gerd Schön
  5. Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle, Germany

    • Martin Hoffmann
    • , Matthias Geilhufe
    • , Sergey Ostanin
    • , Ingrid Mertig
    •  & Arthur Ernst
  6. Institut für Physik, Martin-Luther-Universität Halle-Wittenberg, 06099 Halle, Germany

    • Martin Hoffmann
    • , Wolfram Hergert
    •  & Ingrid Mertig
  7. Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Linnéstraße 2, 04103 Leipzig, Germany

    • Arthur Ernst

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Contributions

W.W. conceived the experiments, and T. Miyamachi, T.S., T. Märkl, A.S. and C.B. carried them out. The data were analysed by T. Miyamachi, T.S., T. Märkl, C.B., T.B. and W.W. Group theory of the crystal field was performed by T.S., T.B., C.B. and W.W. Master equations were analysed by C.K., S.A., M.M. and G.S. Ab initio calculations were performed by M.H., M.G., S.O., W.H., I.M. and A.E. The manuscript was written by T.B. and W.W. Figures were prepared by T. Miyamachi. All authors discussed the results and commented on the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Wulf Wulfhekel.

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    Supplementary Information

    This file contains Supplementary Text and Data, Supplementary Figures 1-3, Supplementary Tables 1-2 and Supplementary References.

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https://doi.org/10.1038/nature12759

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