Figure 6. Energy barriers for a partial dislocation nucleation by crystallographic glide and synchroshear in the MnS, PbS and MgO compounds.

In the energy profiles, the zero point at the total-energy axis marks the total energy of the bulk crystal. The discrete data points correspond to the calculated results. The continuous curves were fitted by spline functions. It is seen that the synchroshear mechanism is energetically favored for dislocation nucleation on {111} planes in MnS. While the pathway of crystallographic glide is an energy-rising process. The case in PbS, however, is the opposite. Due to the strong ionic bonds in MgO, relative slide between adjacent {111} planes is rather difficult.