Atomic-scale studies of (a plus c)-type dislocation dissociation in wurtzite GaN

We performed atomistic modeling and simulations on (a + c)-type dislocations of various core configurations in wurtzite GaN. The atomic-scale stress distribution around the dislocation cores in GaN was for the first time computed using a large-scale atomic/molecular massively parallel simulator. We confirmed from a theoretical viewpoint that the double 5/6-atom ring core structure is stable, whereas the 5/7-atom ring core naturally dissociates. The dissociation of (a + c)-type dislocations with the 5/7-atom ring core structure intrinsically originates from the anisotropy of local atom stress instead of impurities around dislocation cores. (C) 2018 The Japan Society of Applied Physics