Kavli Affiliate: James Analytis| Summary:The cobalt-intercalated transition metal dichalcogenide Co$_x$TaS$_2$ hosts a rich landscape of magnetic phases that depend sensitively on $x$. While the stoichiometric compound with $x=1/3$ exhibits a single magnetic transition, samples with $xleq 0.325$ display two transitions with an anomalous Hall effect (AHE) emerging in the lower temperature phase. Here, we resolve the spin structure in each phase by employing a suite of magneto-optical probes that include the discovery of anomalous magneto-birefringence — a spontaneous time-reversal sensitive rotation of the principal optic axes. A symmetry-based analysis identifies the AHE-active phase as an anisotropic (2+1)textbfQ state, in which magnetic modulation at one wavevector (textbfQ) differs in symmetry from that at the remaining two. The (2+1)textbfQ state naturally exhibits scalar spin chirality as a mechanism for the AHE and expands the classification of multi-Q magnetic phases.| Search Query: arXiv Query: search_query=au:”Analytis James”&id_list=&start=0&max_results=10Read More