Nonvolatile Nematic Order Manipulated by Strain and Magnetic Field in a Layered Antiferromagnet

The operation mechanism of nematic liquid crystals lies in the control of their optical properties by the orientation of underlying nematic directors. In analogy, electronic nematicity refers to a state whose electronic properties spontaneously break rotation symmetries of the host crystalline lattice, leading to anisotropic electronic properties. In this talk, I will present our recent study on the switchable electronic nematic order in the layered chiral antiferromagnet CoTa3S6.[1] The nematicity manifests as both in-plane resistivity anisotropy and optical birefringence, emerging at a characteristic temperature T* distinct from the antiferromagnetic transition. This indicates an additional, independent symmetry-breaking mechanism. I will further show that the nematic order can be tuned either by an in-plane strain that explicitly breaks rotational symmetry or by an in-plane magnetic field, the latter exhibiting a pronounced non-volatile memory effect. Remarkably, a moderate out-of-plane magnetic field restores the three-fold rotational symmetry in transport. The resulting phase diagram reveals a rich interplay between electronic nematicity and the underlying spin textures, establishing CoTa3S6 as a versatile antiferromagnetic platform for exploring tunable symmetry-breaking phenomena.