Dislocation core investigation by geometric phase analysis and the dislocation density tensor

The dislocation density tensor can be employed to 'localize' the dislocation core. We present a method for obtaining experimentally the dislocation core location and size from high resolution transmission electron microscopy observations using geometrical phase analysis. Experimental results are then compared with the results of atomistic simulations, and we also evaluate the applicability of continuum elasticity and its modifications for describing these results. The analysis is performed for partial dislocations in wurtzite GaN. Higher-order gradient elasticity theory is found to be in good agreement with the experimental observations.