Universal giant spin Hall effect in moiré metal

Abstract While moiré phenomena have been extensively studied in low-carrier-density systems such as semiconductors, their implications for metallic systems with large Fermi surfaces remain largely unexplored. Using GPU-accelerated large-scale ab-initio quantum transport simulations, we investigate spin transport in two distinct platforms: twisted bilayer MoTe 2 (semiconductor) and NbX 2 (X = S, Se; metals). In twisted MoTe 2, the spin Hall conductivity (SHC) evolves from 4e4 4 e 4 π at 5. 09° to 10e4 10 e 4 π at 1. 89°. Remarkably, in heavily doped metallic regimes where isolated Chern bands are absent, we observe a universal amplification of the SHC arising from Fermi surface reconstruction under a long-wavelength potential, with the peak SHC tripling from 6e4 6 e 4 π at 5. 09° to 17e4 17 e 4 π at 3. 89°. For moiré metals like twisted NbX 2, we identify a record SHC of −5200 (ℏ / e) S/cm, surpassing all known bulk materials.