Fig. 4.

Theoretical simulations of the ultrafast lattice dynamics. (A) Time evolution of the simulated DW factor of the second-order Bragg reflections for two different excitation fluences. (B) Calculated effective decay time of the DW factor as a function of the lattice temperature. The solid line is a fit using Eq. 1 (see text for details). (C) Calculated time evolution of the lattice pressure as obtained from Eq. 3 (see text). The horizontal dashed line defines the lattice pressure of the system at thermal equilibrium at 300 K before the laser excitation.