Fig. 3: Population and decay of coherent phonons.
From: Valley resolved dynamics of phonon bottleneck in semiconductor molybdenum ditelluride
a Temporal trace of transmission change and b the extracted oscillation signals, measured under 400 nm excitation with fluence of 90 μJ cm–2. Only the kinetics within 10 ps are shown for clarity. c Breathing mode of 0.19 THz and A1g mode of 5.16 THz extracted from a by fast Fourier transform (FFT). Inset, continuous wavelet transform (CWT) of the A1g mode in (b). d Simulated linear dependence of transmittance changes on the separation changes of Te pairs, taking into account that the Te atoms vibrate along the out-of-plane direction while the Mo atoms keep still in A1g mode, as illustrated in the inset. e Two-stage decay of A1g mode extracted from the inset in (c), with biexponential fit. Inset, the Klemens channel for OPs decaying. f Linear dependence of the extracted anharmonic rate on the calculated population of low-frequency APs.
