Ultrafast structural dynamics in InSb probed by time-resolved x-ray diffraction

Ultrafast structural dynamics in laser-perturbed InSb are studied using tim e-resolved x-ray diffraction with a novel femtosecond x-ray source. We repo rt the first observation of a delay in the onset of lattice expansion, whic h we attribute to energy relaxation processes and lattice strain propagatio n. In addition, we observe direct indications of ultrafast disordering on a subpicosecond time scale.