@article{0690785bfca14b9da84409a06b953f48,
title = "Negative flat band magnetism in a spin–orbit-coupled correlated kagome magnet",
abstract = " Electronic systems with flat bands are predicted to be a fertile ground for hosting emergent phenomena including unconventional magnetism and superconductivity 1–15 , but materials that manifest this feature are rare. Here, we use scanning tunnelling microscopy to elucidate the atomically resolved electronic states and their magnetic response in the kagome magnet Co 3 Sn 2 S 2 (refs. 16–20 ). We observe a pronounced peak at the Fermi level, which we identify as arising from the kinetically frustrated kagome flat band. On increasing the magnetic field up to ±8 T, this state exhibits an anomalous magnetization-polarized many-body Zeeman shift, dominated by an orbital moment that is opposite to the field direction. Such negative magnetism is induced by spin–orbit-coupling quantum phase effects 21–25 tied to non-trivial flat band systems. We image the flat band peak, resolve the associated negative magnetism and provide its connection to the Berry curvature field, showing that Co 3 Sn 2 S 2 is a rare example of a kagome magnet where the low-energy physics can be dominated by the spin–orbit-coupled flat band.",
author = "Yin, {Jia Xin} and Zhang, {Songtian S.} and Guoqing Chang and Qi Wang and Tsirkin, {Stepan S.} and Zurab Guguchia and Biao Lian and Huibin Zhou and Kun Jiang and Ilya Belopolski and Nana Shumiya and Daniel Multer and Maksim Litskevich and Cochran, {Tyler A.} and Hsin Lin and Ziqiang Wang and Titus Neupert and Shuang Jia and Hechang Lei and Hasan, {M. Zahid}",
note = "Funding Information: STM experimental and theoretical work at Princeton University was supported by the Gordon and Betty Moore Foundation (GBMF4547/M.Z.H.). ARPES characterization of the sample is supported by the United States Department of Energy (US DOE) under the Basic Energy Sciences programme (grant number DOE/BES DE-FG-02–05ER46200). Work at Renmin University was supported by the Ministry of Science and Technology of China (2016YFA0300504), the National Natural Science Foundation of China (nos. 11574394, 11774423 and 11822412), the Fundamental Research Funds for the Central Universities, and the Research Funds of Renmin University of China (15XNLF06, 15XNLQ07 and 18XNLG14). S.S.T. and T.N. acknowledge support from the European Union{\textquoteright}s Horizon 2020 research and innovation programme (ERC-StG-Neupert-757867-PARATOP). Z.W. and K.J. acknowledge US DOE grant DE-FG02– 99ER45747. We also acknowledge the Natural Science Foundation of China (grant nos. 11790313 and 11774007), the Key Research Program of the Chinese Academy of Sciences (grant no. XDPB08-1), the National Key R&D Program of China (grant nos. 2016YFA0300403 and 2018YFA035601), the Princeton Center for Theoretical Science and the Princeton Institute for the Science and Technology of Materials Imaging and Analysis Center at Princeton University. Muon spin rotation (µSR) experiments were performed at the πE3 beamline of the Paul Scherrer Institute, using the HAL-9500 µSR spectrometer. Z.G. acknowledges R. Scheuermann for support in the µSR experiments. M.Z.H. acknowledges support from Lawrence Berkeley National Laboratory and the Miller Institute of Basic Research in Science at the University of California, Berkeley in the form of a Visiting Miller Professorship. Publisher Copyright: {\textcopyright} 2019, The Author(s), under exclusive licence to Springer Nature Limited.",
year = "2019",
month = may,
day = "1",
doi = "10.1038/s41567-019-0426-7",
language = "English (US)",
volume = "15",
pages = "443--448",
journal = "Nature Physics",
issn = "1745-2473",
publisher = "Nature Publishing Group",
number = "5",
}