Surface tension-induced unique phenomena for edge dislocations in a free-standing thin film

We explore the effects of surface tension and surface elasticity on the elastic behavior of a line edge dislocation buried in a free-standing thin film. Using specific conformal mappings, we derive semi-analytic solutions for the dislocation-induced stress field in the film and the image force acting on the dislocation. It is shown that surface tension and surface elasticity are responsible for significant tractions on the film surface and therefore make an important contribution to the dislocation-induced stress field in the film and to the mobility of the dislocation when the film thickness approaches the nanoscale. In terms of the moving tendency and mobility of the dislocation (defined by the image force acting on the dislocation), it is identified that the effects of surface elasticity always play the role of reducing its mobility without reversing its moving tendency, while those of surface tension would reverse the moving tendency or increase the mobility in certain specific cases. In particular, it is found that for an edge dislocation located on the mid-plane of the film, when the Burgers vector or slip plane of the dislocation is parallel or at a small angle to the surface of the film, the presence of surface tension can alter the dislocation’s equilibrium from a stable to an unstable state as the thickness of the film decreases from the macroscale to the nanoscale (which, incidentally, cannot be achieved by the separate contribution of surface elasticity alone). • Surface tension in line edge dislocation in a free-standing thin film • Surface elasticity in line edge dislocation in a free-standing thin film • Semi-analytic solutions for dislocation-induced stress field in the film • Surface elasticity reduces mobility dislocation without reversing tendency to move • Surface tension reverses moving tendency and increase mobility in certain cases