Exceptional Ideal Strength of Carbon Clathrates

Xavier Blase (1) , Philippe Gillet (2) , A. San Miguel (1) , P. Mélinon (1)

1 LPMCN - Laboratoire de Physique de la Matière Condensée et Nanostructures
2 LST - Laboratoire de Sciences de la Terre

We study by means of ab initio calculations the ideal tensile and shear strengths of the C-46 clathrate phase. While its bulk modulus and elastic constants are smaller than in diamond, its strength is found to be in all directions larger than the critical stresses associated with the diamond {111} planes of easy slip. This can be related to the frustration by the clathrate cage structure of the diamond to graphite instability under hydrostatic stress conditions. The criteria for designing strong materials are discussed.

Mots clés: clathrates; diamond; ab initio; hardness; plastic properties

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

Xavier Blase, Philippe Gillet, A. San Miguel, P. Mélinon. Exceptional Ideal Strength of Carbon Clathrates. Physical Review Letters, 2004, 92, pp.215505. ⟨10.1103/PhysRevLett.92.215505⟩. ⟨hal-00097739⟩