High pressure behavior of CsC8 graphite intercalation compound

N. Rey (1) , Pierre Toulemonde (2) , D. Machon (1) , L. Duclaux (3) , S. Le Floch (1) , V. Pischedda (1) , J.P. Itié (4) , A.-M. Flank (4) , P. Lagarde (4) , W.A. Chrichton (5) , M. Mezouar (5) , T. Strässle (6) , D. Sheptyakov (6) , Gilles Montagnac (7) , A. San-Miguel (1)

1 LPMCN - Laboratoire de Physique de la Matière Condensée et Nanostructures
2 NEEL - MRS - Matériaux, Rayonnements, Structure
3 LCME - Laboratoire de Chimie Moléculaire et Environnement
4 SSOLEIL - Synchrotron SOLEIL
5 ESRF - European Synchrotron Radiation Facility
6 LNS - Laboratory for Neutron Scattering and Imaging [Paul Scherrer Institute]
7 LST - Laboratoire de Sciences de la Terre

The high pressure phase diagram of CsC8 graphite intercalated compound has been investigated at ambient temperature up to 32 GPa. Combining X-ray and neutron diffraction, Raman and X- ray absorption spectroscopies, we report for the first time that CsC8, when pressurized, undergoes phase transitions around 2.0, 4.8 and 8 GPa. Possible candidate lattice structures and the transition mechanism involved are proposed. We show that the observed transitions involve the structural re- arrangement in the Cs sub-network while the distance between the graphitic layers is continuously reduced at least up to 8.9 GPa. Around 8 GPa, important modifications of signatures of the electronic structure measured by Raman and X-ray absorption spectroscopies evidence the onset of a new transition.

Mots clés: graphite interclation compounds; pressure; structural transitions

Domaines: Science des matériaux [cond-mat.mtrl-sci]

N. Rey, Pierre Toulemonde, D. Machon, L. Duclaux, S. Le Floch, et al.. High pressure behavior of CsC8 graphite intercalation compound. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2008, 77 (12), pp.125433. ⟨10.1103/PhysRevB.77.125433⟩. ⟨hal-00180769⟩