3Q magnetic order with spatially alternating spin scalar chirality in overdoped Co_0.336TaS₂

Co_xTaS₂ (x ≈ 1/3) exhibits a spontaneous Hall effect from spin texture in antiferromagnets, with a tetrahedral triple-Q (3Q) order and uniform spin scalar chirality. Upon Co overdoping (x > 1/3), it undergoes a shift in magnetic ordering vectors from Q_m = (1/2, 0, 0) to (1/3, 0, 0). Interestingly, a spontaneous Hall effect disappeared in the overdoped regime, which was originally attributed to the loss of 3Q order. However, a question remains whether a new type of 3Q order can exist with alternating chirality in the overdoped regime. To address this, we investigated Co_0.336TaS₂ using inelastic neutron scattering (INS), neutron diffraction, and optical dichroism to find that INS data and spin-wave simulations support a 3Q order with alternating chirality. Moreover, neutron diffraction data show fieldindependent Bragg peaks, while linear dichroism detects no in-plane anisotropy, consistent with threefold rotation symmetry. Our data support the scenario of an alternating-chirality 3Q order in Co_0.336TaS₂, cancelling the spontaneous Hall effect. This study highlights a combined neutron-optical approach to identify complex spin textures.