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

TitleAnomalous Angular Dependence of the Dynamic Structure Factor near Bragg Reflections: Graphite
Publication TypePalaiseau Article
Acknowledgements

ETSF-I3, ANR ETSF-France

DOI10.1103/PhysRevLett.101.266406
Hambach, R, Giorgetti, C, Hiraoka, N, Cai, YQ, Sottile, F, Marinopoulos, A-G, Bechstedt, F, Reining, L
Year of Publication2008
JournalPhysical Review Letters
Volume101
URLhttp://link.aps.org/abstract/PRL/v101/e266406
Keywordspaper
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.

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