Designing giant Hall response in layered topological semimetals

Abstract Noncoplanar magnets are excellent candidates for spintronics. Particularly important are those with clear electrical transport signatures that can simplify data readout – however, such materials are difficult to find, and even more so to intentionally design. Here, we report a chemical design strategy that allowed us to find a series of new non-coplanar magnets Ln3Sn7 (Ln = Dy, Tb), by targeting layered materials that take decoupled magnetic sublattices with dissimilar single-ion anisotropies, and combining those with a square-net topological semimetal sublattice. Ln3Sn7 shows high carrier mobilities upwards of 17,000 cm2·V−1·s−1, and hosts noncoplanar magnetic order. This results in a strong and sharp Hall effect anomaly, with an anomalous Hall angle of 0.11 and Hall conductivity of over 42,000 Ω−1·cm−1, the highest value reported so far in noncoplanar magnets, and over an order of magnitude larger than the established benchmarks in Mn3Sn and Fe thin films.