Giant and anisotropic many-body spin-orbit tunability in a strongly correlated kagome magnet

Jia-Xin Yin; Songtian S Zhang; Hang Li; Kun Jiang; Guoqing Chang; Bingjing Zhang; Biao Lian; Cheng Xiang; Ilya Belopolski; Hao Zheng; Tyler A Cochran; Su-Yang Xu; Guang Bian; Kai Liu; Tay-Rong Chang; Hsin Lin; Zhong-Yi Lu; Ziqiang Wang; Shuang Jia; Wenhong Wang; M Zahid Hasan

doi:10.1038/s41586-018-0502-7

Giant and anisotropic many-body spin-orbit tunability in a strongly correlated kagome magnet

Nature. 2018 Oct;562(7725):91-95. doi: 10.1038/s41586-018-0502-7. Epub 2018 Sep 12.

Authors

Jia-Xin Yin^#¹, Songtian S Zhang^#¹, Hang Li^#², Kun Jiang³, Guoqing Chang¹, Bingjing Zhang⁴, Biao Lian⁵, Cheng Xiang^{6

7}, Ilya Belopolski¹, Hao Zheng¹, Tyler A Cochran¹, Su-Yang Xu¹, Guang Bian¹, Kai Liu⁴, Tay-Rong Chang⁸, Hsin Lin⁹, Zhong-Yi Lu⁴, Ziqiang Wang³, Shuang Jia^{6

7}, Wenhong Wang², M Zahid Hasan^{10

11}

Affiliations

¹ Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA.
² Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China.
³ Department of Physics, Boston College, Chestnut Hill, MA, USA.
⁴ Department of Physics and Beijing Key Laboratory of Opto-electronic Functional Materials and Micro-nano Devices, Renmin University of China, Beijing, China.
⁵ Princeton Center for Theoretical Science, Princeton University, Princeton, NJ, USA.
⁶ International Center for Quantum Materials and School of Physics, Peking University, Beijing, China.
⁷ CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, China.
⁸ Department of Physics, National Cheng Kung University, Tainan, Taiwan.
⁹ Institute of Physics, Academia Sinica, Taipei, Taiwan.
¹⁰ Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA. mzhasan@princeton.edu.
¹¹ Lawrence Berkeley National Laboratory, Berkeley, CA, USA. mzhasan@princeton.edu.

^# Contributed equally.

PMID: 30209398
DOI: 10.1038/s41586-018-0502-7

Abstract

Owing to the unusual geometry of kagome lattices-lattices made of corner-sharing triangles-their electrons are useful for studying the physics of frustrated, correlated and topological quantum electronic states^1-9. In the presence of strong spin-orbit coupling, the magnetic and electronic structures of kagome lattices are further entangled, which can lead to hitherto unknown spin-orbit phenomena. Here we use a combination of vector-magnetic-field capability and scanning tunnelling microscopy to elucidate the spin-orbit nature of the kagome ferromagnet Fe₃Sn₂ and explore the associated exotic correlated phenomena. We discover that a many-body electronic state from the kagome lattice couples strongly to the vector field with three-dimensional anisotropy, exhibiting a magnetization-driven giant nematic (two-fold-symmetric) energy shift. Probing the fermionic quasi-particle interference reveals consistent spontaneous nematicity-a clear indication of electron correlation-and vector magnetization is capable of altering this state, thus controlling the many-body electronic symmetry. These spin-driven giant electronic responses go well beyond Zeeman physics and point to the realization of an underlying correlated magnetic topological phase. The tunability of this kagome magnet reveals a strong interplay between an externally applied field, electronic excitations and nematicity, providing new ways of controlling spin-orbit properties and exploring emergent phenomena in topological or quantum materials^10-12.