Extended Data Fig. 3: Nearly resonant PL measurement performed with WL excitation in cross-circular polarization setting in device A.
From: Optical control over topological Chern number in moiré materials
a, PL measurement as a function of charge density n at B = 0 performed using approximately 250-nW PL excitation at 1,090 nm combined with further, resonant, circularly polarized 120-nW WL excitation centred around the AP resonance (about 5 meV FWHM, used for optical spin orientation). b, Trion peak energies extracted from non-dispersive Lorentzian fits to the PL spectra, plotted as a function of charge density n for various magnetic fields B. The cusps observed at filling factors ν = −1 and ν = −2/3 disperse according to the Streda formula, confirming that ICI and FCI states remain robust under circularly polarized WL excitation used for optical spin orientation. The extracted Chern numbers are C = −0.99 ± 0.07 for the ν = −1 state and C = −0.63 ± 0.03 for the ν = −2/3 state.
