Fig. 3: Valley-polarized bright exciton to dark exciton scattering dynamics and distribution at low temperature and low exciton density.
a Measured dynamics of the electron density in the K and K’ valley for each spin-split state and hole density in the valence band (dots). The dotted lines show the fit obtained from our model based on rate equations. b Bright (XKb and XK’b), momentum-dark (XK’-K and XK-K’) and spin-dark (XKs and XK’s) dominant exciton populations extracted from our model based on the experimental fit in (a). At 1 ps, we display each excitonic species contribution to the total population. On the right, we present a diagram describing the formation and scattering processes associated to each excitonic populations. Inset: Normalized early time dynamics showing the formation sequence of each excitonic state. c Temporal evolution of the degree of circular polarization and relative population ratio for the XKb bright excitons (yellow) and for the XK’-K and XK-K’ momentum-dark excitons (blue).
