Fig. 2. Magnetic ground state of Co_1/3TaS₂ revealed by neutron diffraction.

a The powder neutron diffraction pattern of Co_1/3TaS₂, measured at 60 K (Gray squares) and 3 K (Red circles). A weak λ/2 signal is highlighted explicitly (see Methods). The solid black line is the diffraction pattern of Co_1/3TaS₂ simulated with the spin configuration shown in h, or equivalently i. The gray (red) vertical solid lines denote the position of nuclear (magnetic) reflections. The full diffraction data can be found in Supplementary Fig. 3. b The single-crystal neutron diffraction pattern at 5 K, demonstrating magnetic Bragg peaks located at the M points. c The intensities of the three magnetic Bragg peaks originating from three different ordering wave vectors. d The temperature-dependent intensities of some magnetic Bragg peaks in single-crystal Co_1/3TaS₂. e, f The temperature dependence of ${\sigma }_{xy}$(H = 0) and $M_z$(H = 0) in Co_1/3TaS₂, measured after field cooling under 5 T. g, h The refined magnetic structures for g 26.5 K < T < 38 K and h T < 26.5 K. i The triple-Q counterpart (tetrahedral) of the single-Q (stripe) ordering shown in h. Note that the spin configurations in h and I give the same powder diffraction pattern.