Figure 1: Interlayer spin-valley physics.

(a) Depiction of the experiment. Spin-valley polarized excitons are resonantly injected in the MoSe₂ layer with a polarized laser (red). The hole transfers to the WSe₂ layer where its spin-valley polarization is measured with another polarized laser (blue), resonant with the WSe₂ excitons. The black arrows depict the real spin of the electrons and holes. (b) Optical microscope image of a MoSe₂–WSe₂ heterostructure (Het.) on SiO₂, showing the different sample regions. (c) The 8-band model of the +K and –K valleys for a nearly aligned MoSe₂–WSe₂ heterostructure, showing the valley dependent optical selection rules (σ± for ±K valley) and real spins (black arrows) for electrons and holes. (d) Degenerate DT spectra from different sample regions for a MoSe₂–WSe₂ heterostructure on sapphire, which are normalized and stacked for comparison. The dashed lines correspond to DT/T=0 for each spectrum. Due to the small isolated WSe₂ area used in the DT study, the laser beam could not completely avoid the heterobilayer region, which results in the artifact of small positive signal at MoSe₂ exciton energy on the WSe₂ sample region.