9 SCIENTIFIC HIGHLIGHT OF THE MONTH Partial dislocations in wurtzite GaN

The atomic structures and energies of 1/6 < 20¯23> and 1/3 < 10¯10> partial dislocations in wurtzite GaN are modelled using an empirical interatomic potential in combination with topological theory and anisotropic elasticity calculations. Twelve stable configurations of the 1/6 < 20¯23> edge and mixed partial dislocations that bound I1 intrinsic basal stacking faults are obtained for each polarity and their core radii, energies, and atomic configurations are given. Moreover, the 1/3 < 10¯10> edge and mixed partial dislocations along the junction lines between inversion domain boundaries (IDBs) and I1 stacking faults are studied. Twenty eight stable junction line configurations have been identified, sixteen of them resulting in stable transformations of the energetically favourable IDB * defect to the electrically active Holt type IDB. The majority of the dislocation core structures possessed either dangling bonds or highly strained bonds. Since reduced coordination or strained bonds can introduce gap states, such dislocations could be electrically active. 1