Shear modulus and hardness of crystals: density functional calculations

Hard materials have many industrial applications wherever resistance to abrasion and wear are important. The experimental data for a wide variety of materials shows that the shear modulus G, which measures the material's resistance to shape change, is correlated to the hardness. In order to deduce a computational scheme for simulating hard materials, the shear modulus associated with the various slip systems encountered in crystalline structures are expressed, for the first time, by means of the microscopic parameters of the chemical bonds, in the framework of the density functional theory. The validity of the theoretical results is tested on diamond, which is the known hardest material. (C) 2000 Elsevier Science Ltd. All rights reserved.