Abstract
The electron energy-loss function of graphite is studied for momentum transfers beyond the first Brillouin zone. We find that near Bragg reflections the spectra can change drastically for very small variations in . The effect is investigated by means of first principle calculations in the random phase approximation and confirmed by inelastic x-ray scattering measurements of the dynamic structure factor . We demonstrate that this effect is governed by crystal local field effects and the stacking of graphite. It is traced back to a strong coupling between excitations at small and large momentum transfers.
- Received 8 February 2008
DOI:https://doi.org/10.1103/PhysRevLett.101.266406
©2008 American Physical Society