Fig. 1: Optical generation and detection of spin transport in a WSe2/WS2 moiré superlattice.
From: Spin transport of a doped Mott insulator in moiré heterostructures
a An optically-generated 1D spin–valley polarization (up arrows) drives a spin current in the doped moiré superlattice (red circles are holes) at the Mott insulator state (one hole per moiré unit cell, \(p/{p}_{0}\) = 1). b A circularly polarized pump beam (yellow) creates a local spin polarization in the hole-doped moiré superlattice. The time-resolved circular dichroism of a probe beam (orange) measures the evolution of the 1D spin polarization in space and time as the pump–probe spatial separation (Δx) is scanned. A voltage V on the capacitor formed by the graphite gate and the moiré superlattice is used to tune the equilibrium hole concentration, p. c Doping-dependent reflection contrast spectrum of device D1, a WSe2/WS2 moiré superlattice. The three moiré exciton states are labeled as I, II, and III. The probe beam is near-resonant with exciton I.
