A new atomistic model for the threading screw dislocation core in wurtzite GaN

We report a new atomistic model for the threading screw dislocation core in wurtzite gallium nitride. By combining elasticity theory and atomistic simulations, we have revealed the new core configuration, with a double 6-atoms ring structure, to be more energetically favourable than the previously known one with a single 6-atoms ring structure, introduced about ten years ago. The new core configuration is fully coordinated and has both Ga–Ga and N–N homo-nuclear bonds in its centre. As the double 6-atoms ring core is free from dangling bonds, it was found to introduce less dispersed energy levels in the bandgap than the single 6-atoms ring core.