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

Hang ChiYunbo OuTim B EldredWenpei GaoSohee KwonJoseph MurrayMichael DreyerRobert E ButeraAlexandre C FoucherHaile AmbayeJong K KeumAlice T GreenbergYuhang LiuMahesh R NeupaneGeorge J de CosterOwen A VailPatrick J TaylorPatrick A FolkesCharles RongGen YinRoger K LakeFrances M RossValeria LauterDon HeimanJagadeesh S Moodera
Published in: Nature communications (2023)
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.
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