Fig. 5: Time evolution of the transient photoemission intensity from excited states.
a Time- and angle-resolved photoemission (tr-ARPES) dispersion at a time delay Δt = 300 fs. The energy-momentum windows from which the data shown in b–g were extracted are shown as an overlay. Surface-state bands, bulk-derived surface resonances and pure bulk states are denoted as SS, SR, and BS, respectively. High-symmetry directions [purple (green) coloring for \(\overline{\,\text{M}\,}\)-\(\overline{{{\Gamma }}}\) (\(\overline{{{\Gamma }}}\)-\(\overline{\,\text{K}\,}\))], energies and band features are indicated in all panels. b Tr-ARPES intensities as a function of delay time for different states at energy E6. c Similar traces for the inner branch of the surface state extracted at +k∥,x (blue) and −k∥,x (red) wave vectors. Tr-ARPES intensities of the inner branch of the surface state (d) and bulk state (e) along different momentum directions. Traces in b–e are fit to an exponential decay convolved with a Gaussian profile to account for the time resolution. Decay times represented according to spin character of the states (f) or the momentum direction (g). Vertical error bars correspond to ± one standard deviation. Each error bar along the energy axis indicates the size of the integrated energy window from which the decay time has been obtained. Dashed line in black (orange) is a fit to a model including (not including) nonthermal effects. Note that the orange dashed line corresponds to the prediction of a two-temperature (2T) model.
