Elastic energy of a screw dislocation near a planar interface: effect of inner cut-off

The energy of a screw dislocation near the planar interface separating two isotropic media of different shear moduli is calculated via the work done by surface forces during a virtual process of dislocation creation. In addition to the only term usually considered arising from the cut across the material, contributions from the inner and outer cut-off surfaces have been taken into account. The force on the dislocation arising from the difference in elastic moduli is found neither to diverge nor to vanish at the interface. The critical stress to force the dislocation into a medium with higher modulus is discussed and compared with other calculations based on non local elasticity or a Peierls model. This calculation method of the total elastic strain energy finds a useful application in atomistic calculations of dislocations making possible accurate energy comparisons.