Nonmonotonic Scaling of the Anomalous Hall Effect in a Bicollinear Antiferromagnet

TL;DR

This study explores the anomalous Hall effect in FeTe thin films, revealing nonmonotonic behavior linked to Berry curvature and magnetic structure, with implications for spintronics.

Contribution

It demonstrates the nonmonotonic scaling of AHE in FeTe, a bicollinear antiferromagnet, and connects it to topological band structure and magnetic canting.

Findings

Large AHE below Neel temperature (~60 K)

Nonlinear AHE at high fields near 49 K

Field-induced canted magnetic moment observed

Abstract

An anomalous Hall effect (AHE) in antiferromagnetic (AF) systems with no net magnetization is of considerable interest for both fundamental physics and spintronic applications. Of particular interest is the two-dimensional van der Waals antiferromagnet FeTe that has an unusual fully magnetically compensated bicollinear AF structure and exhibits pronounced Kondo interaction leading to 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 Neel temperature (T_N ~ 60 K) and, strikingly, becomes nonlinear at high fields within a narrow temperature window around 49 K, deviating from conventional AHE scaling behavior versus its longitudinal conductivity. Linear fits reveal a pronounced negative peak in the intercept, accompanied by a field-induced canted magnetic moment. The AHE responses are related to the Berry curvature derived from FeTe's topological band structure, highlighting the intricate interplay between topology, magnetism, and electronic transport.