Strain-tunable Berry curvature in quasi-two-dimensional chromium telluride

• Published in: Nature communications Vol. 14; no. 1; pp. 3222 - 8
• Main Authors: Chi, Hang, Ou, Yunbo, Eldred, Tim B., Gao, Wenpei, Kwon, Sohee, Murray, Joseph, Dreyer, Michael, Butera, Robert E., Foucher, Alexandre C., Ambaye, Haile, Keum, Jong, Greenberg, Alice T., Liu, Yuhang, Neupane, Mahesh R., de Coster, George J., Vail, Owen A., Taylor, Patrick J., Folkes, Patrick A., Rong, Charles, Yin, Gen, Lake, Roger K., Ross, Frances M., Lauter, Valeria, Heiman, Don, Moodera, Jagadeesh S.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 03.06.2023; Nature Publishing Group; Nature Portfolio
• Subjects: 142/126; 147/137; 147/138; 639/301/119/2792; 639/301/119/2793; 639/301/119/544; 639/301/119/997; Chromium; Coercivity; Curvature; Electromagnetism; ferromagnetism; First principles; Hall effect; Humanities and Social Sciences; Intermetallic compounds; Magnetic materials; magnetic properties and materials; Magnetic transitions; Magnetism; Magnetization; MATERIALS SCIENCE; multidisciplinary; Room temperature; Scanning transmission electron microscopy; Science; Science (multidisciplinary); Substrates; surfaces, interfaces and thin films; Tellurides; Temperature dependence; Thin films; topological matter; Topology; Transition metal compounds; Transmission electron microscopy
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-38995-4

Magnetic transition metal chalcogenides form an emerging platform for exploring spin-orbit driven Berry phase phenomena owing to the nontrivial interplay between topology and magnetism. Here we show that the anomalous Hall effect in pristine Cr 2 Te 3 thin films manifests a unique temperature-dependent sign reversal at nonzero magnetization, resulting from the momentum-space Berry curvature as established by first-principles simulations. The sign change is strain tunable, enabled by the sharp and well-defined substrate/film interface in the quasi-two-dimensional Cr 2 Te 3 epitaxial films, revealed by scanning transmission electron microscopy and depth-sensitive polarized neutron reflectometry. This Berry phase effect further introduces hump-shaped Hall peaks in pristine Cr 2 Te 3 near the coercive field during the magnetization switching process, owing to the presence of strain-modulated magnetic layers/domains. The versatile interface tunability of Berry curvature in Cr 2 Te 3 thin films offers new opportunities for topological electronics. Chromium tellurides are a particularly promising family of quasi-2D magnetic materials; towards the single van der Waals layer limit, they preserve magnetic ordering, some even above room temperature, and exhibit a variety of intrinsic topological properties. Here, Hang Chi, Yunbo Ou and co-authors demonstrate a strain tunable Berry curvature induced reversal of the anomalous Hall effect in Cr 2 Te 3 .