Theoretical Strength and Cleavage of Diamond

R. H. Telling (1) , C. J. Pickard (1) , M. C. Payne (1) , J. E. Field (1)

1 Cavendish Laboratory

The theoretical strength of diamond has been calculated for the <100>, <110>, and <111> directions using a first principles approach and is found to be strongly dependent on crystallographic direction. This elastic anisotropy, found at large strains, and particularly the pronounced minimum in cohesion in the <111> direction, is believed to be the reason for the remarkable dominance of the 111 cleavage plane when diamond is fractured. The extra energy required to cleave a crystal on planes other than 111 is discussed with reference to simple surface energy calculations and also the introduction of bond-bending terms.

Domaines: Mécanique des matériaux [physics.class-ph]

R. H. Telling, C. J. Pickard, M. C. Payne, J. E. Field. Theoretical Strength and Cleavage of Diamond. Physical Review Letters, 2000, 84 (22), pp.5160-5163. ⟨10.1103/physrevlett.84.5160⟩. ⟨hal-01615574⟩