What does an $$\left( {\vec a + \vec c} \right)$$ dislocation core look like in wurtzite GaN ?

Here we present results on the first atomic simulation of the threading $$\left( {\vec a + \vec c} \right)$$ –mixed dislocation cores in wurtzite GaN. These calculations are based on a modified Stillinger-Weber potential. For this dislocation two core configurations are shown to be stable, one with a complex double 5/6-atoms rings and the other with a 5/7-atom rings structures. These two cores do not contain wrong bonds.