Figure 7. GPFE curves for MnS and PbS.

(a) The diagrams of energy versus shear parameter of MnS and (b) for PbS. The relative higher stacking fault energy and lower γ_us/γ_ut value for PbS, compared with that for MnS indicate that cross-slip and twinning is favored in PbS crystal and in MnS crystal, respectively.