# Anomalous Angular Dependence of the Dynamic Structure Factor near Bragg Reflections: Graphite

 Title Anomalous Angular Dependence of the Dynamic Structure Factor near Bragg Reflections: Graphite Publication Type Palaiseau Article Acknowledgements ETSF-I3, ANR ETSF-France DOI 10.1103/PhysRevLett.101.266406 Hambach, R, Giorgetti, C, Hiraoka, N, Cai, YQ, Sottile, F, Marinopoulos, A-G, Bechstedt, F, Reining, L Year of Publication 2008 Journal Physical Review Letters Volume 101 URL http://link.aps.org/abstract/PRL/v101/e266406 Keywords paper Abstract The electron energy-loss function of graphite is studied for momentum transfers q beyond the first Brillouin zone. We find that near Bragg reflections the spectra can change drastically for very small variations in q. 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 S(q,$\omega$). 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. Full Text
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