Tetrahedral triple-Q magnetic ordering and large spontaneous Hall conductivity in the metallic triangular antiferromagnet Co1/3TaS2

TL;DR

This paper reports the discovery of tetrahedral triple-Q magnetic ordering in metallic Co1/3TaS2, leading to a large spontaneous Hall effect, supported by experimental and theoretical analysis of its magnetic and electronic structure.

Contribution

It presents the first example of tetrahedral triple-Q magnetic order in a metallic TLAF and links it to topological Hall conductivity, supported by experimental and theoretical insights.

Findings

Observation of tetrahedral triple-Q magnetic order in Co1/3TaS2

Detection of a large spontaneous Hall conductivity in the material

Theoretical and experimental validation of the magnetic ground state

Abstract

The triangular lattice antiferromagnet (TLAF) has been the standard paradigm of frustrated magnetism for several decades. The most common magnetic ordering in insulating TLAFs is the 120 structure. However, a new triple-Q chiral ordering can emerge in metallic TLAFs, representing the short wavelength limit of magnetic skyrmion crystals. We report the metallic TLAF Co1/3TaS2 as the first example of tetrahedral triple-Q magnetic ordering with the associated topological Hall effect (non-zero {\sigma}_{xy}(H=0)). We also present a theoretical framework that describes the emergence of this magnetic ground state, which is further supported by the electronic structure measured by angle-resolved photoemission spectroscopy. Additionally, our measurements of the inelastic neutron scattering cross section are consistent with the calculated dynamical structure factor of the tetrahedral triple-Q state.