Charles Tam: Giant Anomalous Hall Effect in a Disordered Kagome Metal

Date and Time

Friday, October 30, 2026

12:00 - 1:00 (PST)

Elings 1605

Giant anomalous hall effect in a disordered kagome metal

Abstract: Materials with a large anomalous hall effect (AHE) are candidates for spintronics and magnetic field sensing. Microscopically, the AHE may have an intrinsic origin, from Berry curvature from the band structure, or an extrinsic origin, which comes from scattering. There exists an e 2 /h/layer quantum limit that an anomalous Hall conductivity originating from Berry curvature cannot exceed. Therefore, to push past this quantum limit, extrinsic contribution must be considered.

In the disordered topological kagome metal Zr 2 Fe 3.6 Ge 0.4, we observe a giant anomalous Hall conductivity of 2100 -1 cm -1 at 2K, which falls to 1600 Q -1 cm -1 at 300K, corresponding to an anomalous Hall angle of 26% at 2K, and 17% at 300K. This result is record breaking in kagome metals. We attribute this to a large intrinsic component that nears the quantum limit, originating from several Weyl nodes calculated to be near the Fermi level, in addition to a substantial extrinsic contribution resulting from skew scattering from site mixing, the primary disorder mode in Zr 2 Fe 3.6 Ge 0.4 Our results demonstrate the role of disorder in engineering materials with desirable electrical transport properties.