Abstract

The kagome lattice is a two-dimensional network of corner-sharing triangles1 that is known to host exotic quantum magnetic states2,3,4. Theoretical work has predicted that kagome lattices may also host Dirac electronic states5 that could lead to topological6 and Chern7 insulating phases, but these states have so far not been detected in experiments. Here we study the d-electron kagome metal Fe3Sn2, which is designed to support bulk massive Dirac fermions in the presence of ferromagnetic order. We observe a temperature-independent intrinsic anomalous Hall conductivity that persists above room temperature, which is suggestive of prominent Berry curvature from the time-reversal-symmetry-breaking electronic bands of the kagome plane. Using angle-resolved photoemission spectroscopy, we observe a pair of quasi-two-dimensional Dirac cones near the Fermi level with a mass gap of 30 millielectronvolts, which correspond to massive Dirac fermions that generate Berry-curvature-induced Hall conductivity. We show that this behaviour is a consequence of the underlying symmetry properties of the bilayer kagome lattice in the ferromagnetic state and the atomic spin–orbit coupling. This work provides evidence for a ferromagnetic kagome metal and an example of emergent topological electronic properties in a correlated electron system. Our results provide insight into the recent discoveries of exotic electronic behaviour in kagome-lattice antiferromagnets8,9,10 and may enable lattice-model realizations of fractional topological quantum states11,12.

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References

  1. 1.

    & Crystal Structures. I. Patterns and Symmetry Ch. 5 (Mineralogical Society of America, 1996)

  2. 2.

    Kagome- and triangular-lattice Heisenberg antiferromagnets: ordering from quantum fluctuations and quantum-disordered ground states with unconfined bosonic spinons. Phys. Rev. B 45, 12377–12396 (1992)

  3. 3.

    et al. Fractionalized excitations in the spin-liquid state of a kagome-lattice antiferromagnet. Nature 492, 406–410 (2012)

  4. 4.

    , & Quantum spin liquid states. Rev. Mod. Phys. 89, 025003 (2017)

  5. 5.

    et al. Theoretical prediction of a strongly correlated Dirac metal. Nat. Commun. 5, 4261 (2014)

  6. 6.

    & Topological insulator on the kagome lattice. Phys. Rev. B 80, 113102 (2009)

  7. 7.

    , & Intrinsic quantum anomalous Hall effect in the kagome lattice Cs2LiMn3F12. Phys. Rev. Lett. 115, 186802 (2015)

  8. 8.

    , & Large anomalous Hall effect in a non-collinear antiferromagnet at room temperature. Nature 527, 212–215 (2015)

  9. 9.

    et al. Large anomalous Hall effect driven by a nonvanishing Berry curvature in the noncolinear antiferromagnet Mn3Ge. Sci. Adv. 2, e1501870 (2016)

  10. 10.

    et al. Evidence for magnetic Weyl fermions in a correlated metal. Nat. Mater. 16, 1090–1095 (2017)

  11. 11.

    & High-temperature fractional quantum Hall states. Phys. Rev. Lett. 106, 236802 (2011)

  12. 12.

    , , , & Topology and interactions in a frustrated slab: tuning from Weyl semimetals to C > 1 fractional Chern insulators. Phys. Rev. Lett. 114, 016806 (2015)

  13. 13.

    The band theory of graphite. Phys. Rev. 71, 622–634 (1947)

  14. 14.

    , , & Quantized Hall conductance in a two-dimensional periodic potential. Phys. Rev. Lett. 49, 405–408 (1982)

  15. 15.

    et al. Experimental observation of the quantum anomalous Hall effect in a magnetic topological insulator. Science 340, 167–170 (2013)

  16. 16.

    , , , & Anomalous Hall effect. Rev. Mod. Phys. 82, 1539–1592 (2010)

  17. 17.

    & High pressure X-ray diffraction study of all FeSn intermetallic compounds and one FeSn solid solution. J. Alloys Compd. 422, 132–144 (2006)

  18. 18.

    , & Mössbauer effect study of Fe3Sn2. J. Phys. F 8, 323–336 (1978)

  19. 19.

    et al. Observation of various and spontaneous magnetic Skyrmionic bubbles at room temperature in a frustrated kagome magnet with uniaxial magnetic anisotropy. Adv. Mater. 29, 1701144 (2017)

  20. 20.

    et al. The giant anomalous Hall effect in the ferromagnet Fe3Sn2—a frustrated kagome metal. J. Phys. Condens. Matter 23, 112205 (2011)

  21. 21.

    , , , & Anomalous Hall effect in a ferromagnetic Fe3Sn2 single crystal with a geometrically frustrated Fe bilayer kagome lattice. Phys. Rev. B 94, 075135 (2016)

  22. 22.

    , & Proper scaling of the anomalous Hall effect. Phys. Rev. Lett. 103, 087206 (2009)

  23. 23.

    & Anomalous Hall effect in ferromagnetic metals: role of phonons at finite temperature. J. Phys. Soc. Jpn 81, 083704 (2012)

  24. 24.

    et al. Coexisting massive and massless Dirac fermions in symmetry-broken bilayer graphene. Nat. Mater. 12, 887–892 (2013)

  25. 25.

    , , , & Ferromagnetism of Fe3Sn and alloys. Sci. Rep. 4, 7024 (2014)

  26. 26.

    et al. Massive Dirac fermion on the surface of a magnetically doped topological insulator. Science 329, 659–662 (2010)

  27. 27.

    et al. Hedgehog spin texture and Berry’s phase tuning in a magnetic topological insulator. Nat. Phys. 8, 616–622 (2012)

  28. 28.

    et al. Bandgap opening in graphene induced by patterned hydrogen adsorption. Nat. Mater. 9, 315–319 (2010)

  29. 29.

    , , , & YCr6Ge6 as a candidate compound for a kagome metal. J. Phys. Soc. Jpn 82, 023705 (2013)

  30. 30.

    & Quantum spin Hall effect in graphene. Phys. Rev. Lett. 95, 226801 (2005)

  31. 31.

    Model for a quantum Hall effect without Landau levels: condensed-matter realization of the “parity anomaly”. Phys. Rev. Lett. 61, 2015–2018 (1988)

  32. 32.

    , & Magnetic properties of hexagonal and cubic Fe3Ge. J. Phys. F 6, 2165–2177 (1976)

  33. 33.

    , & Non-collinearity and spin frustration in the itinerant kagome ferromagnet Fe3Sn2. J. Phys. Condens. Matter 21, 452202 (2009)

  34. 34.

    , , , & Electron-magnon scattering and magnetic resistivity in 3d ferromagnets. Phys. Rev. B 66, 024433 (2002)

  35. 35.

    et al. Observation of Dirac cone electronic dispersion in BaFe2As2. Phys. Rev. Lett. 104, 137001 (2010)

  36. 36.

    et al. Observation of Dirac cone band dispersions in FeSe thin films by photoemission spectroscopy. Phys. Rev. B 93, 104513 (2016)

  37. 37.

    , , , & Quasiparticle dynamics in graphene. Nat. Phys. 3, 36–40 (2007)

  38. 38.

    et al. Semiconducting graphene from highly ordered substrate interactions. Phys. Rev. Lett. 115, 136802 (2015)

  39. 39.

    , & Angle-resolved photoemission studies of the cuprate superconductors. Rev. Mod. Phys. 75, 473–541 (2003)

  40. 40.

    et al. Observation of the magnon Hall effect. Science 329, 297–299 (2010)

  41. 41.

    et al. Topological magnon bands in a kagome lattice ferromagnet. Phys. Rev. Lett. 115, 147201 (2015)

  42. 42.

    , , & Magnetic structure of the kagome lattice antiferromagnet potassium jarosite KFe3(OH)6(SO4)2. Phys. Rev. B 61, 12181–12186 (2000)

  43. 43.

    et al. Spin-1/2 kagome-like lattice in volborthite Cu3V2O7(OH)2 ∙ 2H2O. J. Phys. Soc. Jpn 70, 3377–3384 (2001)

  44. 44.

    , & Topological quantization of the spin Hall effect in two-dimensional paramagnetic semiconductors. Phys. Rev. B 74, 085308 (2006)

  45. 45.

    , , , & Anomalous Hall effect in a two-dimensional Dirac band: the link between the Kubo-Streda formula and the semiclassical Boltzmann equation approach. Phys. Rev. B 75, 045315 (2007)

  46. 46.

    Berry curvature on the Fermi surface: anomalous Hall effect as a topological Fermi-liquid property. Phys. Rev. Lett. 93, 206602 (2004)

  47. 47.

    et al. The anomalous Hall effect and magnetic monopoles in momentum space. Science 302, 92–95 (2003)

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Acknowledgements

We are grateful to X.-G. Wen and E. Tang for discussions. This research was funded in part by the Gordon and Betty Moore Foundation EPiQS Initiative, grant GBMF3848 to J.G.C. and NSF grant DMR-1554891. L.Y., J.L. and F.v.C. acknowledge support by the STC Center for Integrated Quantum Materials, NSF grant number DMR-1231319. L.Y. acknowledges support by the Tsinghua Education Foundation. M.K. acknowledges a Samsung Scholarship from the Samsung Foundation of Culture. This research used resources of the Advanced Light Source, which is a DOE Office of Science User Facility under contract number DE-AC02-05CH11231. A portion of this work was performed at the National High Magnetic Field Laboratory, which is supported by NSF cooperative agreement number DMR-1157490, the State of Florida and the US Department of Energy.

Author information

Author notes

    • Junwei Liu
    •  & Felix von Cube

    Present addresses: Department of Physics, Hong Kong UST, Clear Water Bay, Hong Kong, China (J.L.); Hitachi High-Technologies Europe GmbH, Krefeld, Germany (F.v.C.).

    • Linda Ye
    •  & Mingu Kang

    These authors contributed equally to this work.

Affiliations

  1. Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA

    • Linda Ye
    • , Mingu Kang
    • , Junwei Liu
    • , Christina R. Wicker
    • , Takehito Suzuki
    • , Liang Fu
    • , Riccardo Comin
    •  & Joseph G. Checkelsky
  2. Harvard John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA

    • Felix von Cube
    •  & David C. Bell
  3. Advanced Light Source, E. O. Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA

    • Chris Jozwiak
    • , Aaron Bostwick
    •  & Eli Rotenberg
  4. Center for Nanoscale Systems, Harvard University, Cambridge, Massachusetts 02138, USA

    • David C. Bell

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Contributions

L.Y., T.S. and C.R.W. grew the single crystals. L.Y. characterized the materials, performed the transport and magnetic measurements and analysed the resultant data. M.K., C.J., A.B. and E.R. performed the ARPES experiment and analysed the resultant data. J.L. and L.Y. performed the theoretical calculations. F.v.C. and D.C.B. performed the electron microscopy study. All authors contributed to writing the manuscript. L.F., R.C. and J.G.C. supervised the project.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Riccardo Comin or Joseph G. Checkelsky.

Reviewer Information Nature thanks E. Bergholtz, B. Lake and O. Rader for their contribution to the peer review of this work.

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https://doi.org/10.1038/nature25987

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