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

TL;DR

This study demonstrates that strain can tune the Berry curvature and anomalous Hall effect in Cr2Te3 thin films, revealing a temperature-dependent sign reversal linked to magnetic domains and interface effects, with implications for topological electronics.

Contribution

It introduces strain as a control parameter for Berry curvature in Cr2Te3 thin films, combining experimental and first-principles methods to reveal tunable topological phenomena.

Findings

Temperature-dependent sign reversal of anomalous Hall effect

Strain-tunable Berry curvature in Cr2Te3 films

Observation of hump-shaped Hall peaks near coercive field

Abstract

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 Cr2Te3 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 Cr2Te3 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 Cr2Te3 near the coercive field during the magnetization switching process, owing to the presence of strain-modulated magnetic domains. The versatile interface tunability of Berry curvature in Cr2Te3 thin films offers new opportunities for topological electronics.