Equilibrium critical size of coherent InSb/GaSb quantum dot

We present a finite element method to simulate the strain field in InSb/GaSb quantum dots in the framework of anisotropic elasticity, before and after the onset of plastic relaxation. Taking the interaction between dislocation and free surface into consideration, the model directly calculates the residual strain in the dislocated system. Based on the energy balance between the two isolated states, the equilibrium critical size is determined. In the criterion, only the non-elastic dislocation core energy should be considered separately. The results are in satisfactory agreement with experimental data.