Shear deformation properties of α- and β-silicon nitride single crystals were investigated by using the classical molecular dynamics method. Four cases of shearing directions were analyzed, which were reported to be slip system on the basis of experimental observations. The simulation results showed that shear deformation does not occur in one of the experimentally predicted slips (α: {1¯1•1}<11•0>). In this case the crystal was

broken abruptly under shear deformation. In the case of the β crystals (β: {10•0}<00•1>), a sharp slip with edge dislocation could be found. The dislocation core width and speed were estimated. Finally one of the classical molecular dynamics results was compared with the corresponding first principle density functional calculation results, and it was shown that the validity about shearing classical molecular dynamics simulation of the 3-body interatomic potential was proposed by Vashishta.

Molecular Dynamics Simulation of Shearing Deformation Process of Silicon Nitride Single Crystal. S.Ogata, H.Kitagawa, N.Hirosaki, Y.Hatanaka, T.Umezu: Computational Materials Science, 2002, 23[1-4], 146-54