Switching from extrinsic to intrinsic anomalous Hall effect around Lifshitz transition in a Kagome-lattice ferromagnet.

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 1206 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 a unified theoretical model and sheds light on exploring the essence of anomalous Hall effect, especially in Kagome-lattice magnets. [ABSTRACT FROM AUTHOR]