Emergent zero-field anomalous Hall effect in a reconstructed rutile antiferromagnetic metal

Abstract

The anomalous Hall effect (AHE) that emerges in antiferromagnetic metals shows intriguing physics and offers numerous potential applications. Magnets with a rutile crystal structure have recently received attention as a possible platform for a collinear-antiferromagnetism-induced AHE. RuO₂ is a prototypical candidate material, however the AHE is prohibited at zero field by symmetry because of the high-symmetry [001] direction of the Néel vector at the ground state. Here, we show AHE at zero field in Cr-doped rutile, Ru_0.8Cr_0.2O₂. The magnetization, transport and density functional theory calculations indicate that appropriate doping of Cr at Ru sites reconstructs the collinear antiferromagnetism in RuO₂, resulting in a rotation of the Néel vector from [001] to [110] while maintaining a collinear antiferromagnetic state. The AHE with vanishing net moment in the Ru_0.8Cr_0.2O₂ exhibits an orientation dependence consistent with the [110]-oriented Hall vector. These results demonstrate that material engineering by doping is a useful approach to manipulate AHE in antiferromagnetic metals.

The anomalous Hall effect is typically associated with ferromagnets and referred to as anomalous due to its persistence even after the applied magnetic field is removed, due to the net magnetization of the ferromagnet. Recently there has been much interest in antiferromagnets that can host an anomalous Hall effect, despite a vanishing magnetization, and here, Wang et al observe an anomalous Hall effect in collinearly antiferromagnetic chromium doped RuO₂.