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

TL;DR

This study demonstrates electrical control of the topologically nontrivial 3Q magnetic phase in intercalated van der Waals antiferromagnet Cox-TaS2 through ionic gating, revealing phase boundaries and discontinuities in the magnetic structure.

Contribution

It is the first to show electrical control of scalar spin chirality in an antiferromagnetic metal via ionic gating in Cox-TaS2.

Findings

Ionic gating covers the entire 3Q phase space.

Discovered an adiabatic discontinuity at the 3Q-1Q phase boundary.

Controlled topological magnetic phases electrically.

Abstract

Van der Waals (vdW) magnets have opened a new avenue of opportunities encompassing various interesting phases. Co1/3TaS2-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 CoxTaS2 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.