Speaker
Description
Diffraction-before-destruction schemes rely on collecting data before radiation damage develops. This condition is readily satisfied for atomic motion, making serial femtosecond crystallography highly successful in investigating photoinduced structural changes in both organic and inorganic matter. It is less clear, however, whether the condition also holds for the electronic contributions to the structure factors. Using broadband, temporally chirped X-ray pulses, achieving few-fs resolution, we compare the structurally forbidden reflections of elemental silicon, which are predominantly sensitive to valence electron density, with simultaneously measured allowed lattice Bragg peaks. We observe photoinduced valence bond depletion on sub-10-fs timescales, well before significant lattice disorder takes place. Our results establish the temporal limits of diffraction-before-destruction of electronic orders and provide a new route to disentangling electronic and structural dynamics in crystalline solids at few to sub-femtosecond timescales.
| Scientific Topics | Solid State Physics |
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