Chiral superlattice-induced spin-polarized current from collinear antiferromagnet

Chirality is a fascinating concept in fundamental science. A long-standing question is the connection between chirality and magnetism, as both evoke a sense of rotation. In fact, Louis Pasteur, who discovered molecular chirality, already attempted to control chirality of crystals by magnetic field. Since then, understanding how chirality couples to spin or magnetism has been a profound question, spanning particle physics, quantum materials and asymmetric chemistry. We report our surprising discovery that a natural chiral superlattice can induce spin-polarized current from the collinear antiferromagnet (AFM) UOTe. Using transmission electron microscopy and optical circular dichroism, we identify a long-range planar chiral superlattice in UOTe, which can be viewed as frozen chiral phonons at finite wave vector. UOTe without chiral superlattice is a conventional collinear AFM without spin-polarized current or Berry curvature. However, the chiral superlattice couples strongly to itinerant Dirac electron spins in the collinear AFM, inducing a sizable spin-polarized current. Furthermore, the chiral superlattice modifies the quantum geometry, inducing total Berry curvature that emerges abruptly from the collinear AFM, generating an anomalous Hall angle ~0.14, among the largest in bulk magnets. Theoretically, UOTe's PT-symmetric Dirac fermion acts as a singularity, generating strong low-energy responses under weak PT breaking by the chiral superlattice. Our result demonstrates a new chiral superlattice path towards functionalizing AFMs. More broadly, our study bridges chirality, superlattices, and unconventional magnetism, inspiring new chiral magnetic physics and device concepts.