Nonmonotonic scaling of the anomalous Hall effect in a bicollinear antiferromagnet

An anomalous Hall effect (AHE) in antiferromagnetic (AF) systems without net magnetization is of considerable interest for fundamental physics and spintronic applications. Of particular interest is the two-dimensional van der Waals antiferromagnet iron telluride (FeTe), which has an unusual magnetically compensated bicollinear AF structure and claimed Kondo interactions that cause strong band renormalization. Here, we investigate the AHE in epitaxial FeTe thin films grown by molecular beam epitaxy. A large anomalous Hall conductivity is exhibited below the Néel temperature (T_N ∼ 60 kelvins) and, notably, becomes nonlinear at high magnetic fields within a narrow temperature window around 49 kelvins, deviating from conventional AHE scaling behavior versus the longitudinal conductivity. The accompanying field-induced canted magnetic moment activates these AHE responses by tuning the Berry curvature derived from FeTe's topological band structure once the zero-field symmetry constraint is lifted. The unconventional scaling of AHE highlights the intricate interplay between antiferromagnetism, topology, and electronic transport in FeTe.