Telling RH, Pickard CJ, Payne MC, Field JE
Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB3 OHE, United Kingdom.
Phys Rev Lett. 2000 May 29;84(22):5160-3. doi: 10.1103/PhysRevLett.84.5160.
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.
利用第一性原理方法计算了金刚石在<100>、<110>和<111>方向上的理论强度，发现其强烈依赖于晶体学方向。这种在大应变下发现的弹性各向异性，特别是<111>方向上内聚能的明显最小值，被认为是金刚石断裂时111解理面显著占主导地位的原因。结合简单的表面能计算以及键弯曲项的引入，讨论了在111以外的平面上解理晶体所需的额外能量。
