In my talk, I will present the ultrafast formation dynamics of dark interlayer excitons in twisted WSe2/MoS2 heterostructures in space and time. First, I will report on the identification of a hallmark signature of the moiré superlattice that is imprinted onto the momentum-resolved interlayer exciton photoemission signal. With this data, we reconstruct the electronic part of the exciton wavefunction, and relate its extension to the moiré wavelength of the heterostructure. Second, I will show that interlayer excitons are effectively formed via exciton-phonon scattering, and subsequent interlayer tunneling at the interlayer hybridized ΣW valleys on the sub-50 fs timescale.
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