Magnetic ground states of a model for MNb3S6 (M = Co, Fe, Ni)

The transition-metal-intercalated dichalcogenide CoNb3S6 is a triangular antiferromagnet (AFM) that has recently been shown to exhibit a large anomalous Hall effect (AHE) below the Neel temperature, even though the response to an external field is very small. This suggests that there is an interesting magnetic structure that interacts with the electronic structure to yield the AHE, as collinear AFMs cannot exhibit a nonzero AHE. We propose a model for magnetic transition-metal-intercalated dichalcogenides and examine its ground state as a function of interaction parameters. The model exhibits transitions between planar spin spirals, nonplanar spin spirals, and a particular noncoplanar so-called 3q state. This latter state must exhibit a nonzero AHE, while the spin spirals do not.

Automated summary

The recently discovered triangular antiferromagnet CoNb3S6 has shown a large anomalous Hall effect due to its interesting magnetic structure that interacts with the electronic structure. A proposed model reveals various ground states, including planar and nonplanar spin spirals, as well as a distinct noncoplanar 3q state, which can exhibit a nonzero anomalous Hall effect.