2025/04/22 by Ning Mao, Xu Cheng, Mao, Ning +9
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Graphene research and applications #Magnetic properties of thin films #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Quantum and electron transport phenomena
paper · pdf · doi:10.48550/arxiv.2504.16179
openalex publication_date 2025/04/22 · openalex created_date 2025/10/11 · openalex updated_date 2026/07/28
While moiré phenomena have been extensively studied in low-carrier-density systems such as graphene and 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 MoTe2 (semiconductor, from lightly to heavily doping) and NbX2 (X = S, Se; metals). In twisted MoTe2, the spin Hall conductivity (SHC) evolves from 4\tfrace4π at 5.09^∘ to 10\tfrace4π at 1.89^∘, driven by the emergence of multiple isolated Chern bands. Remarkably, in heavily doped metallic regimes--without isolated Chern bands--we observe a universal amplification of the spin Hall effect from Fermi surface reconstruction under long-wavelength potential, with the peak SHC tripling from 6\tfrace4π at 5.09^∘ to 17\tfrace4π at 3.89^∘. For prototypical moiré metals like twisted NbX2, we identify a record SHC of -17\tfrace4π (-5200 (ℏ / e)S/cm in 3D units), surpassing all known bulk materials. These results establish moiré engineering as a powerful strategy for enhancing spin-dependent transport, and advancing ab-initio methodologies to bridge atomic-scale precision with device-scale predictions in transport simulations.