Massive Dirac fermions in a ferromagnetic kagome metal

By Linda Ye, Mingu Kang, Junwei Liu, F. V. Cube, Christina R. Wicker, Takehito Suzuki, C. Jozwiak, A. Bostwick, Eli Rotenberg, David Bell and 3 more. Nature, 2017

909 citations recorded by the source corpus.

The kagome lattice is a two-dimensional network of corner-sharing triangles that is known to host exotic quantum magnetic states. Theoretical work has predicted that kagome lattices may also host Dirac electronic states that could lead to topological and Chern 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 antiferromagnets and may enable lattice-model realizations of fractional topological quantum states.

Subfields: Atomic and Molecular Physics, and Optics, Condensed Matter Physics

View Paper: https://www.semanticscholar.org/paper/1449964c82d7a37a5eb133b3929dff52fcf3c7a7

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In Atomic and Molecular Physics, and Optics

1. Binghai Yan
2. B. Ortiz
3. L. Balents
4. Ashvin Vishwanath
5. N. P. Armitage
6. E. Mele
7. Xianhui Chen
8. Xiao-Liang Qi

In Condensed Matter Physics

1. Binghai Yan
2. L. Balents
3. Ashvin Vishwanath
4. Simon Trebst
5. Xianhui Chen

Citations in the corpus

• Three-state nematicity and magneto-optical Kerr effect in the charge density waves in kagome superconductors (2022, background): “There has been recent interest in the magnetic kagome systems from the perspective of the topological electronic structures such as the magnetic Weyl semimetals Mn 3 Sn[2], Co 3 Sn 2 S 2 [3] and strongly correlated flat bands in Fe 3 Sn 2 and FeSn [4–7].”