Anomalous Hall effect in Kagome lattice ferromagnet

What is it about?

The Lifshitz transition, wherein the Fermi level shifts from the conduction band to the valence band with increasing temperature, offers a promising platform for exploring the interplay between Fermi-surface topology and Berry curvature field. Here, we highlight the discovery of a switching from extrinsic to intrinsic anomalous Hall effect around a Lifshitz transition in the ferromagnetic Kagome-lattice LiMn6Sn6. The temperature-induced Lifshitz transition manifests prominently as a polarity flip of the ordinary Hall resistivity around 100 K, verifying a vital alteration of the Fermi surface topology. Furthermore, LiMn6Sn6 showcases an extrinsic anomalous Hall effect underneath around 100 K, potentially premised on enhanced skew-scattering of spin-cluster with scalar spin chirality that scales quadratically with longitudinal conductivity, which acquires a maximum anomalous Hall conductivity of 1,206 Ω−1 cm−1. Whereas above the critical temperature, the anomalous Hall conductivity maintains virtually constant at approximately 396 Ω−1 cm−1 with an anomalous Hall ratio reaching 8.5%, which substantiates the dissipationless intrinsic Berry curvature mechanism from electronic bands of the Kagome plane with broken time-reversal symmetry avoiding crossing near the Fermi level. Our work provides different perspective on the extrinsic-intrinsic crossover within the framework of unified theoretical model, and sheds light on exploring the essence of anomalous Hall effect, especially in Kagome-lattice magnets.

Featured Image

Photo by Vishnu Mohanan on Unsplash

Photo by Vishnu Mohanan on Unsplash

Why is it important?

Our findings offer up a platform for the exploration of scaling behavior in anomalous Hall effect, particularly at the critical crossover between extrinsic and intrinsic mechanisms.

Perspectives