Letter | Published:

# Long-distance spin transport through a graphene quantum Hall antiferromagnet

## Abstract

Because of their ultrafast intrinsic dynamics and robustness against stray fields, antiferromagnetic insulators1,2,3 are promising candidates for spintronic components. Therefore, long-distance, low-dissipation spin transport and electrical manipulation of antiferromagnetic order are key research goals in antiferromagnetic spintronics. Here, we report experimental evidence of robust spin transport through an antiferromagnetic insulator, in our case the gate-controlled state that appears in charge-neutral graphene in a magnetic field4,5,6. Utilizing quantum Hall edge states as spin-dependent injectors and detectors, we observe large, non-local electrical signals across charge-neutral channels that are up to 5 μm long. The dependence of the signal on magnetic field, temperature and filling factor is consistent with spin superfluidity1,2,4,7,8,9,10 as the spin-transport mechanism. This work demonstrates the utility of graphene in the quantum Hall regime as a powerful model system for fundamental studies in antiferromagnetic spintronics.

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## Change history

• ### 09 July 2018

In the version of this Letter originally published, the number in the middle yellow box of Fig. 2d was incorrectly given as +2; it should have been 0. This has now been corrected.

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## Acknowledgements

We thank H. Chen for helpful discussions. The work is supported by SHINES, which is an Energy Frontier Research Center funded by the Department of Energy (DOE) Basic Energy Sciences (BES) under Award #SC0012670. S.C. is supported by DOE BES under award ER 46940-DE-SC0010597 to study the quantum Hall effect in graphene. A.H.M. acknowledges partial support by the Welch Foundation under grant TBF1473. Part of this work was performed at the NHMFL, which is supported by NSF/DMR-0654118, the State of Florida, and the DOE. Growth of hBN crystals was supported by the Elemental Strategy Initiative conducted by the MEXT, Japan and a Grant-in-Aid for Scientific Research on Innovative Areas ‘Science of Atomic Layers’ from the Japan Society for the Promotion of Science (JSPS).

## Author information

Y.B., A.H.M. and C.N.L. conceived the experiment. P.S., S.C. and D.Sh fabricated samples. K.T. and G.V. assisted with sample fabrication. P.S., J.Y., S.C., R.C. and D.Sm performed measurements. K.W. and T.T. provided materials. Y.B., P.S., A.H.M., M.B., R.L. and C.N.L. analysed and interpreted the data. P.S., Y.B., A.H.M., R.L. and C.N.L. wrote the manuscript. All authors discussed and commented on the manuscript.

Correspondence to Roger K. Lake or Yafis Barlas or Allan H. MacDonald or Chun Ning Lau.

## Supplementary information

1. ### Supplementary Information

Supplementary Figures 1–5

2. ### Spin transport through graphene antiferromagnetic insulator

Movie demonstrating spin transport

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• #### DOI

https://doi.org/10.1038/s41567-018-0161-5