Widely Tunable Berry Curvature in the Magnetic Semimetal Cr1+δTe2

• DOI: 10.1002/adma.202207121
• Publication Date: 2023-01-16T05:09:25Z
• Authors: Yuita Fujisawa; Markel Pardo‐Almanza; Chia‐Hsiu Hsu; Atwa Mohamed; Kohei Yamagami; Anjana Krishnadas; Guoqing Chang; Feng‐Chuan Chuang; Khoong Hong Khoo; Jiadong Zang; Anjan Soumyanaray...; Yoshinori Okada
• Keywords: 02 engineering and technology; 0210 nano-technology

AbstractMagnetic semimetals have increasingly emerged as lucrative platforms hosting spin‐based topological phenomena in real and momentum spaces. Cr1+δTe2 is a self‐intercalated magnetic transition metal dichalcogenide (TMD), which exhibits topological magnetism and tunable electron filling. While recent studies have explored real‐space Berry curvature effects, similar considerations of momentum‐space Berry curvature are lacking. Here, the electronic structure and transport properties of epitaxial Cr1+δTe2 thin films are systematically investigated over a range of doping, δ (0.33 – 0.71). Spectroscopic experiments reveal the presence of a characteristic semi‐metallic band region, which shows a rigid like energy shift with 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 link between the 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. These 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.