Widely tunable Berry curvature in the magnetic semimetal Cr₁₊δTe₂

• Main Authors: Fujisawa, Yuita, Pardo-Almanza, Markel, Hsu, Chia-Hsiu, Mohamed, Atwa, Yamagami, Kohei, Krishnadas, Anjana, Chang, Guoqing, Chuang, Feng-Chuan, Khoo, Khoong Hong, Zang, Jiadong, Soumyanarayanan, Anjan, Okada, Yoshinori
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2023
• Subjects: Science::Physics::Electricity and magnetism; Engineering::Materials::Magnetic materials; Anomalous Hall Effects; Berry Curvature
• Online Access: https://hdl.handle.net/10356/164952
• Institution: Nanyang Technological University

Magnetic 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 momentumspace Berry curvature in magnetic TMDs and provide a unique platform for intertwining topological physics in real and momentum spaces.