Widely Tunable Berry curvature in the Magnetic Semimetal Cr 1+ δ Te 2 .

Magnetic semimetals have increasingly emerged as lucrative platforms hosting spin-based topological phenomena in real- and momentum spaces. Cr 1+ δ Te 2 is a self-intercalated magnetic transition metal dichalcogenide (TMD), which exhibits topological magnetism, tunable electron filling, and magnetic frustration etc. While recent studies have explored real-space Berry curvature effects in this material, similar considerations of momentum-space Berry curvature have been lacking. Here, we systematically investigate the electronic structure and transport properties of epitaxial Cr 1+ δ Te 2 thin films over a wide range of doping, δ (0.33 - 0.71). Spectroscopic experiments reveal the presence of a characteristic semi-metallic band region near the Brillouin zone edge, which shows a rigid band like energy shift as a function of δ. Transport experiments show that the intrinsic component of the anomalous Hall effect (AHE) is sizable, and undergoes a sign flip across δ. Finally, density functional theory calculations establish a causal link between the observed doping evolution of the band structure and AHE: the AHE sign flip is shown to emerge from the sign change of the Berry curvature, as the semi-metallic band region crosses the Fermi energy. Our findings underscore the increasing relevance of momentum-space Berry curvature in magnetic TMDs and provide a unique platform for intertwining topological physics in real and momentum spaces. This article is protected by copyright. All rights reserved.