Designing giant Hall response in layered topological semimetals

Noncoplanar magnets are excellent candidates for spintronics. However, such materials are difficult to find, and even more so to intentionally design. Here, we report a chemical design strategy that allows us to find a series of noncoplanar magnets-Ln₃Sn₇ (Ln = Dy, Tb)-by targeting layered materials that have 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 giant Hall response with an anomalous Hall angle of 0.17 and Hall conductivity of over 42,000 Ω^-1 ⋅ cm^-1-a value over an order of magnitude larger than the established benchmarks in Co₃Sn₂S₂ and Fe thin films.