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Seminar | Materials Science Division

Anomalous Hall Effect in New Ferromagnetic Weyl Semimetals with Additional Degrees of Freedom

MSD Seminar

Abstract: Recently, record-high anomalous Hall effect (AHE) induced by intrinsic topological Weyl nodes is found in ferromagnetic Weyl semimetals (FM WSMs). However, it is not clear how robustly the intrinsic AHE can hold against extrinsic AHE contributed by spin-orbit coupled potentials. Besides, the underlying mechanism of the AHE found in FM WSMs so far is through the Berry curvature, which is not unique to FM WSMs and a Hall response solely induced by Weyl nodes has yet to be found.

In two separate works, we target a new class of FM WSMs REAl(Ge/Si) (RE = rare earths), the properties of which can be finely adjusted by changing the rare earths or the ratio between germanium and silicon. In PrAlGe1-xSix (x = 0-1), we unveiled the first transition from intrinsic to extrinsic AHE in FM WSMs and the role of extrinsic mechanism in the context of FM WSMs. In CeAlSi, we found that the Fermi level can be tuned as close as 1 meV away from the Weyl nodes. Moreover, a novel anomalous Hall response appears (disappears) as the Fermi level is close to (away from) the Weyl nodes. The close link between a novel AHE and the proximity of Weyl nodes to the Fermi level establishes a new transport response solely induced by Weyl nodes.