Plethora of tunable Weyl fermions in kagome magnet Fe₃Sn₂ thin films

Journal Article · Tue Nov 15 00:00:00 UTC 2022 · npj Quantum Materials

DOI: https://doi.org/10.1038/s41535-022-00521-y · OSTI ID:2419534

Ren, Zheng  ^[1]; Li, Hong ^[2]; Sharma, Shrinkhala ^[2]; Bhattarai, Dipak ^[3]; Zhao, He ^[2]; Rachmilowitz, Bryan ^[2]; Bahrami, Faranak  ^[2]; Tafti, Fazel  ^[2]; Fang, Shiang  ^[4]; Ghimire, Madhav Prasad ^[5]; Wang, Ziqiang ^[2]; Zeljkovic, Ilija  ^[2]

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1. Boston College, Chestnut Hill, MA (United States); OSTI
2. Boston College, Chestnut Hill, MA (United States)
3. Tribhuvan Univ., Kirtipur (Nepal)
4. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
5. Tribhuvan Univ., Kirtipur (Nepal); Leibniz Inst. for Solid State and Materials Research (IFW), Dresden (Germany)

Interplay of magnetism and electronic band topology in unconventional magnets enables the creation and fine control of novel electronic phenomena. In this work, we use scanning tunneling microscopy and spectroscopy to study thin films of a prototypical kagome magnet Fe₃Sn₂. Our experiments reveal an unusually large number of densely-spaced spectroscopic features straddling the Fermi level. These are consistent with signatures of low-energy Weyl fermions and associated topological Fermi arc surface states predicted by theory. By measuring their response as a function of magnetic field, we discover a pronounced evolution in energy tied to the magnetization direction. Electron scattering and interference imaging further demonstrates the tunable nature of a subset of related electronic states. Our experiments provide a direct visualization of how in-situ spin reorientation drives changes in the electronic density of states of the Weyl fermion band structure. Combined with previous reports of massive Dirac fermions, flat bands, and electronic nematicity, our work establishes Fe₃Sn₂ as an interesting platform that harbors an extraordinarily wide array of topological and correlated electron phenomena.

• Research Organization: Boston College, Chestnut Hill, MA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: FG02-99ER45747
• OSTI ID: 2419534
• Journal Information: npj Quantum Materials, Journal Name: npj Quantum Materials Journal Issue: 1 Vol. 7; ISSN 2397-4648
• Publisher: Nature Publishing GroupCopyright Statement
• Country of Publication: United States
• Language: English