Events

Chirality is a fascinating topic in fundamental sciences. The interplay between chirality and magnetism has been a profound question, spanning particle physics, chemistry and biology. Here, we study this interplay in the context of unconventional magnetism and quantum geometry. We report our surprising observation a natural chiral superlattice can induce large spin-polarized current and giant Berry curvature from the collinear antiferromagnet (AFM) UOTe, despite near-zero magnetization. Using TEM and optical CD, we identify a long-range planar chiral superlattice in UOTe, which can be viewed as frozen chiral phonons at finite wave vector. Interestingly, as electrons move through the chiral superlattice, its wavefunction strongly rotates, leading to nontrivial space quantum geometry (possibly hybrid real-momentum space) that manifests as a giant nonlinear Hall effect. With the onset of AFM order that breaks time-reversal symmetry, the anomalous Hall effect (total Berry curvature) emerges abruptly near Neel temperature, generating an anomalous Hall angle ~0.14, among the largest in bulk magnets. Furthermore, the chiral superlattice couples strongly to itinerant Dirac electron spins in the collinear AFM, inducing a sizable spin-polarized current. We present a feasible design principle that can discover similar superlattice in other materials. Our result points to a new chiral superlattice path towards compensated topological magnetism with nontrivial real space quantum geometry.