Fig. 5: Polarization and energy-dependent carrier decay dynamics.
From: Ultrafast photoinduced band splitting and carrier dynamics in chiral tellurium nanosheets
Representative polarization-resolved TR (ΔR/R0) traces of Te samples around the fundamental gap a and higher energy transition region b. Dashed red lines are the multi-exponential fits of each corresponding data over a long delay range, as described in the main text. Insets show the initial decay responses of each corresponding trace. Around the band-edge region, a majority of the TR signal relaxes within first 30 ps due to ultrafast intraband thermalization followed by interband recombination. Around the higher energy transition, only a fraction of the maximum TR signal decays rapidly, predominantly by intervalley scattering accompanied by intraband thermalization, while the rest of the signal recovers on the order of a nanosecond due to interband recombination. c Schematic drawing of carrier excitation and relaxation processes within the extended bulk band structure of Te around high symmetry points in the Brillouin zone. Pump excitation is indicated by vertical red arrows and probe excitation is shown by vertical purple arrows. Intervalley forward and return scattering processes are also shown by green solid and dashed arrows.
