Structural dynamics of nanoscale gold by ultrafast electron crystallography

By employing ultrafast electron crystallography in a transmission geometry for ultra-thin (2–3 nm) gold, here we show that structural dynamics of the transverse atomic motions and the atomic displacements around the equilibrium position can be separated from the measured change in Bragg diffraction, the positions and intensities of the peaks, respectively. The rate of intensity change provides the electron-lattice equilibration time whereas the observed lattice expansion, which occurs on a slower time scale, maps the delayed response of transverse lattice strain. These textbook-type results provide the microscopic stress–strain profile that is critical for understanding dynamical deformations and the effect of morphological structures at surfaces.