Topological ferromagnetic Kondo lattice
Date:
Magnetic topological semimetals have recently emerged as a topic of central interest in condensed matter physics, but have mostly been explored in weakly-correlated materials. Strong interacting systems, such as Kondo lattices, can host tunable unconventional topological states thanks to their rich phase diagram with multiple intertwined degrees of freedom. Here we unravel the existence of Kondo-induced Weyl-loop states in CeCo2As2. Using angle-resolved photoemission spectroscopy and first-principle calculation, we visualize f-orbital-dominated heavy nodal rings near the Fermi level in the magnetic Kondo lattice phase. Remarkably, by tuning the ratio of Ce/La, we observe a substantial enhancement of anomalous Hall conductivity in the coherent Kondo lattice regime. The value of the Hall conductivity quantitatively matches with the first-principle calculation that optimized with our ARPES results and can be attributed to the large Berry curvature (BC) density engendered by the topological nodal rings. Our results promote $CeCo_2As_2$ as a topological Kondo magnet candidate and underpin the realization of various topological responses in a highly sensitive ferromagnetic Kondo lattice setting.
The preprint can be found here and the work has been presented on APS march meeting 2023. Current submitted to peer review journals.