Deterministic control of antiferromagnetic domain walls by circular phonons
In an antiferromagnet, areas with different orientations of the antiferromagnetic Néel vector, which plays the role of the order parameter, can coexist, thus forming antiferromagnetic domains separated by domain walls. This suggests that antiferromagnets can possess the functionalities of magnetic storage media. Whether one can benefit from these functionalities crucially depends on the availability of efficient means for deterministic control of antiferromagnetic domain walls. Here, we demonstrate an approach to deterministically control domain walls in the van der Waals antiferromagnet Ni-doped $MnPS_3$ via dynamic engineering of the crystal lattice. By resonantly exciting a pair of nearly degenerate orthogonal infrared-active $A_u$ and $B_u$ phonon modes with circularly polarized mid-infrared light, we induce helicity-dependent reconfiguration of 180° antiferromagnetic domains, providing evidence for a phonon-induced effective field conjugate to the Néel order parameter. The domain kinetics exhibit a pronounced helicity asymmetry governed by the interplay between domain-wall elasticity and defect-mediated pinning, enabling small phonon-driven perturbations to accumulate into stable domain transformations. Our results establish dynamic lattice control and defect engineering as means for deterministic control of antiferromagnetic order.