Large anomalous Hall effect in the chiral-lattice antiferromagnet CoNb3S6

Nirmal J Ghimire,A S Botana,J S Jiang,J F Mitchell,Junjie Zhang,Y.-S Chen

doi:10.1038/s41467-018-05756-7

Nirmal J Ghimire, A S Botana + Show 4 more

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https://doi.org/10.1038/s41467-018-05756-7

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Abstract

An ordinary Hall effect in a conductor arises due to the Lorentz force acting on the charge carriers. In ferromagnets, an additional contribution to the Hall effect, the anomalous Hall effect (AHE), appears proportional to the magnetization. While the AHE is not seen in a collinear antiferromagnet, with zero net magnetization, recently it has been shown that an intrinsic AHE can be non-zero in non-collinear antiferromagnets as well as in topological materials hosting Weyl nodes near the Fermi energy. Here we report a large anomalous Hall effect with Hall conductivity of 27 Ω−1 cm−1 in a chiral-lattice antiferromagnet, CoNb3S6 consisting of a small intrinsic ferromagnetic component (≈0.0013 μB per Co) along c-axis. This small moment alone cannot explain the observed size of the AHE. We attribute the AHE to either formation of a complex magnetic texture or the combined effect of the small intrinsic moment on the electronic band structure.

Highlights

An ordinary Hall effect in a conductor arises due to the Lorentz force acting on the charge carriers
The anomalous Hall effect (AHE) is a signature of emergent electromagnetic fields in solids that affect the motion of the electrons, and it has been a recent topic of intense study in the context of the topological materials[1,2]
A sketch of the crystal structure adopted by CoNb3S6 is shown in Fig. 1a, where the Co atoms occupy the octahedral position between the triangular prismatic layers of the parent compound 2H-NbS2

Summary

Introduction

An ordinary Hall effect in a conductor arises due to the Lorentz force acting on the charge carriers. We report a large anomalous Hall effect with Hall conductivity of 27 Ω−1 cm−1 in a chiral-lattice antiferromagnet, CoNb3S6 consisting of a small intrinsic ferromagnetic component (≈0.0013 μB per Co) along c-axis. This small moment alone cannot explain the observed size of the AHE. Recent observations of the large anomalous Hall effect in metals with possible Weyl[12,13,14] and massive Dirac fermions[15,16] and/or complex spin textures, e.g., skyrmion bubbles[17], have generated interest in such materials, especially for the role of correlated topological states in the emergent electronic properties. Based on its chiral crystal structure and the calculated band structure, we attribute the AHE in CoNb3S6 either to the formation of a complex magnetic texture or to an influence of the small intrinsic ferromagnetic moment on the underlying electronic band structure

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