Flat band separation and robust spin Berry curvature in bilayer kagome metals

Journal Article · 18 May 2023 · Nature Physics

DOI: https://doi.org/10.1038/s41567-023-02053-z · OSTI ID:1993973

Di Sante, Domenico  ^[1]; Bigi, Chiara  ^[2]; Eck, Philipp ^[3]; Enzner, Stefan  ^[3]; Consiglio, Armando  ^[3]; Pokharel, Ganesh ^[4]; Carrara, Pietro  ^[5]; Orgiani, Pasquale  ^[6]; Polewczyk, Vincent ^[6]; Fujii, Jun  ^[7]; King, Phil D. C.  ^[2]; Vobornik, Ivana  ^[7]; Rossi, Giorgio  ^[5]; Zeljkovic, Ilija  ^[8]; Wilson, Stephen D.  ^[4]; Thomale, Ronny  ^[3]; Sangiovanni, Giorgio  ^[3]; Panaccione, Giancarlo  ^[7]; Mazzola, Federico  ^[9]

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1. Univ. of Bologna (Italy); Flatiron Institute, New York, NY (United States)
2. Univ. of St. Andrews, Scotland (United Kingdom)
3. Univ. of Wurzburg (Germany)
4. Univ. of California, Santa Barbara, CA (United States)
5. Univ. degli Studi di Milano (Italy); Consiglio Nazionale delle Ricerche (CNR), Trieste (Italy)
6. Consiglio Nazionale delle Ricerche (CNR), Trieste (Italy). TASC Laboratory
7. Consiglio Nazionale delle Ricerche (CNR), Trieste (Italy)
8. Boston College, Chestnut Hill, MA (United States)
9. Consiglio Nazionale delle Ricerche (CNR), Trieste (Italy); Ca' Foscari University of Venice (Italy)

Kagome materials have emerged as a setting for emergent electronic phenomena that encompass different aspects of symmetry and topology. It is debated whether the XV₆Sn₆ kagome family (where X is a rare-earth element), a recently discovered family of bilayer kagome metals, hosts a topologically non-trivial ground state resulting from the opening of spin–orbit coupling gaps. These states would carry a finite spin Berry curvature, and topological surface states. Here we investigate the spin and electronic structure of the XV₆Sn₆ kagome family. We obtain evidence for a finite spin Berry curvature contribution at the centre of the Brillouin zone, where the nearly flat band detaches from the dispersing Dirac band because of spin–orbit coupling. In addition, the spin Berry curvature is further investigated in the charge density wave regime of ScV₆Sn₆ and it is found to be robust against the onset of the temperature-driven ordered phase. Utilizing the sensitivity of angle-resolved photoemission spectroscopy to the spin and orbital angular momentum, our work unveils the spin Berry curvature of topological kagome metals and helps to define its spectroscopic fingerprint.

• Research Organization: Boston College, Chestnut Hill, MA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES); European Union (EU); German Research Foundation (DFG); National Science Foundation (NSF); Gauss Centre for Supercomputing
• Grant/Contract Number: SC0020130; 897276; DMR-1906325
• OSTI ID: 1993973
• Alternate ID(s): OSTI ID: 2481102
• Journal Information: Nature Physics, Vol. 19, Issue 8; ISSN 1745-2473
• Publisher: Nature Publishing Group (NPG)Copyright Statement
• Country of Publication: United States
• Language: English