Nodal-line resonance generating the giant anomalous Hall effect of Co3Sn2 S2
Journal
Physical Review B
Journal Volume
107
Journal Issue
21
Start Page
214441
ISSN
2469-9950
2469-9969
Date Issued
2023-06-27
Author(s)
F. Schilberth
M.-C. Jiang
S. Minami
M. A. Kassem
F. Mayr
T. Koretsune
Y. Tabata
T. Waki
H. Nakamura
R. Arita
I. Kézsmárki
S. Bordács
Abstract
Giant anomalous Hall effect (AHE) and magneto-optical activity can emerge in magnets with topologically nontrivial degeneracies. However, identifying the specific band-structure features such as Weyl points, nodal lines, or planes which generate the anomalous response is a challenging issue. Since the low-energy interband transitions can govern the static AHE, we addressed this question in the prototypical magnetic Weyl semimetal Co3Sn2S2 also hosting nodal lines by broadband polarized reflectivity and magneto-optical Kerr effect spectroscopy with a focus on the far-infrared range. In the linear dichroism spectrum we observe a strong resonance at 40 meV, which also appears in the optical Hall conductivity and primarily determines the static AHE, and thus confirms its intrinsic origin. Our material-specific theory reproduces the experimental data remarkably well and shows that strongly tilted nodal-line segments around the Fermi energy generate the resonance. While the Weyl points only give vanishing contributions, these segments of the nodal lines gapped by the spin-orbit coupling dominate the low-energy optical response and generate the giant AHE.
SDGs
Publisher
American Physical Society (APS)
Type
journal article