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Chiral electronic excitations and strong electron-phonon coupling to Weyl fermions in the kagome semimetal
Phys. Rev. B 112, 214404 – Published 1 December, 2025
DOI: https://doi.org/10.1103/wkzr-vfgn
Abstract
We present results of a Raman-scattering study of the Kagome ferromagnet , with a focus on electronic and phononic excitations and their interplay. We provide a theoretical analysis of the electronic-band structure, enabling a semiquantitative explanation of the spectra. A prominent feature in the electronic spectra is a redistribution of spectral weight from low to high energies in all polarization configurations starting at the Curie temperature . In the symmetry-resolved spectra, the suppression of the continuum in the ferromagnetic state arises from the redistribution of electronic states below , while a strong enhancement of the continuum is linked to the dynamics of fermions near the Fermi level being characterized by spin-momentum locking near Weyl points. The phonon modulates the position of these Weyl points and couples strongly to the related fermions close to . These results allow a comprehensive understanding of the bulk band-structure evolution as a function of temperature in , offering key insights for further studies of the driving force behind the long-range magnetic order and novel topological states in this compound.