Symmetry-driven spin anisotropic magnetotransport in the quantum spin Hall insulator 1T'-WTe2

Journal article, 2026

We present a comprehensive analysis of magnetotransport across monolayer 1T^'-WTe2, highlighting the role of nonsymmorphic symmetries in governing edge-state spin behavior. By comparing the electronic transmission in nanoribbons with edges along the crystallographic ŷ and x̂ directions, our analysis reveals a pronounced anisotropy in the magnetic-field response. The ŷ-edge ribbon exhibits significant spin splitting of the edge-state bands in both energy and momentum space, together with a strong angular dependence of the conductance. The observed magnetotransport response indicates a spin quantization axis that aligns with the out-of-plane spin quantization axis reported in previous experimental studies. In contrast, the x̂-edge ribbon shows negligible spin splitting with magnetic fields, which is attributed to nonsymmorphic symmetries such as glide mirror and screw rotation, which protects degeneracies along the Γ-X direction, even when time-reversal symmetry is broken. The energy-resolved current density and angular transmission analysis confirm that this anisotropy originates from edge states, while bulk states remain largely insensitive to the field orientation. Our results establish direct transport spectroscopy based evidence of nonsymmorphic symmetry-protected spin degeneracy in 1T^'-WTe2, and underscore its promise for spintronic devices that leverage symmetry-protected and directionally selective transport channels.