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 center 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.
@article{arxiv.2305.15345,
title = {Flat band separation and robust spin-Berry curvature in bilayer kagome metals},
author = {Domenico Di Sante and Chiara Bigi and Philipp Eck and Stefan Enzner and Armando Consiglio and Ganesh Pokharel and Pietro Carrara and Pasquale Orgiani and Vincent Polewczyk and Jun Fujii and Phil D. C King and Ivana Vobornik and Giorgio Rossi and Ilija Zeljkovic and Stephen D. Wilson and Ronny Thomale and Giorgio Sangiovanni and Giancarlo Panaccione and Federico Mazzola},
journal= {arXiv preprint arXiv:2305.15345},
year = {2023}
}