456-molecular dynamics study on the 60° dislocation motion in Si crystal

The motion characteristics of Si 60° dislocations at the differential temperatures and shear stresses applied by Parrinello-Rahman method were simulated by utilizing molecular dynamics (MD) model. It is found that the 60° dislocations velocity is directly proportional to the applied shear stress, and three different tendencies associated with the dislocation velocity affected by applied shear stress at the differential temperatures are presented: (1) The velocity increases as the temperature increases when the shear stress is much lower than 0.6 GPa; (2) The dislocation velocity decreases as the temperature increases when the shear stress is around 0.6 GPa. The phonon drag effect takes place in this case; (3) The dislocation velocity becomes insensitive to the system temperature when the shear stress approaches to 2 GPa.