Structural dynamics and transient electric-field effects in ultrafast electron diffraction from surfaces

Ultrafast electron microscopy and diffraction provide direct visualization of structural dynamics with atomic scale resolution. In surface diffraction studies, it may have been assumed that the generation of transient electric fields could mask some features of structural dynamics. Here, we show that such an effect is irrelevant when ultrafast electron microscopy is invoked. It is also demonstrated that for the diffraction investigation of surfaces at grazing angles it is straightforward to observe the structural dynamics provided that simple controls are made for diffraction dependencies on order and intensity, and a comparison with the behavior of the undiffracted beam.