Electrical control of topological 3Q state in intercalated van der Waals antiferromagnet Co_x-TaS₂

Van der Waals (vdW) magnets have opened a new avenue of opportunities encompassing various interesting phases. Co_1/3TaS₂-an intercalated metallic vdW antiferromagnet-is one of the latest additions to this growing list of materials due to its unique topologically nontrivial triple-Q (3Q) ground state. This 3Q tetrahedral structure, which critically depends on the Co content, yields the highest-density Skyrmion lattice with scalar spin chirality, resulting in a noticeable anomalous Hall effect. In this work, we demonstrate control of this topological phase via ionic gating. Using four Co_xTaS₂ devices with different Co compositions, we show that ionic gating can cover the entire 3Q topological phase and reveal the nature of the thermodynamically inaccessible phase space. Another striking finding in our data is the existence of an adiabatic discontinuity in the phase boundary between the 3Q and 1Q phases. Our work constitutes one of the first examples of electrical control of scalar spin chirality using an antiferromagnetic metal.