Hidden orbital Rashba effect-induced large anomalous Hall effect in topological ferromagnet Fe₃GeTe₂

Fe₃GeTe₂ (FGT) is a compelling two-dimensional van der Waals material exhibiting both ferromagnetism and nontrivial band topology, giving rise to phenomena such as a significant anomalous Hall effect (AHE). Motivated by the large AHE observed in FGT, we perform a first-principles investigation to elucidate its origin. We identify the orbital Rashba effect, specifically a hidden orbital Rashba effect, as the source of the large Berry curvature driving the AHE. While previous studies on the AHE in FGT have focused on Berry curvature contributions at the K point in the Brillouin zone [1], we reveal a comparable contribution arising from the hidden orbital Rashba effect near the Γ point. Atom-resolved calculations demonstrate that the large Berry curvature originates from orbital hybridization induced by the hidden orbital Rashba textures of the Te atoms. Notably, the dominant bands contributing to the Berry curvature around both Γ and K points are fully spin-polarized, contrasting with the conventional AHE induced by spin magnetism. These findings establish orbital magnetism as the driving force behind the AHE in FGT, providing crucial insights for understanding novel phenomena in topological magnetic materials and guiding the search for materials with enhanced topological properties.

[1] K. Kim et al., Nat. Mater. 17, 794 (2018).