Internal structures of moire trions determine their quantum dynamics

The superlattice imposes a periodic spatial modulation of both energy and optical selection rules. In almost all previous studies, excitons and trions are assumed to be tightly bound composite particles, moving in a smoothly varying potential. However, the energy modulation for doped carriers (i.e., electrons and holes) and optical created electron-hole pairs are different. Thus, they may be localized within different sites within a supercell, leading to either charge-transfer excitons or trions. Here, we identify two types of trions confined by the moir'e potential of a 57.5° twisted MoSe2 bilayer. Using two-dimensional coherent electronic spectroscopy with a variety of pulse sequences and polarization schemes, we discover these two types of trions exhibit distinct quantum dynamics. Excitation-density dependent homogeneous linewidth of charge transfer trions reveal a stronger many-body interaction among them than that of tight-bound trions. Our study suggests that moir'e superlattices may offer a new platform for realizing spin-photon transduction.