(a) The electron density distribution upon the 5% excitation in rhombohedral GeTe. The red arrows indicate the force acting on atoms. (b) The change of potential energy surface of GeTe due to electronic excitation. (c) The trajectories of atomic motions during the TDDFT-MD simulation of the phase transition in GeTe with a 5% excitation. Time evolution of (d) average force, (e) bond length, (f) temperature, (g) kinetic energy, and (h) momentum during the TDDFT-MD in GeTe under a 5% excitation. All panels are reproduced from Ref. [44] with permission from the American Physical Society.