First-principles calculations of the energetics of the In-terminated GaN(0001), $\left(0001\mathrm{}̱\right),$ $\left(101\mathrm{}̱1\right),$ and $\left(10\mathrm{}\underset{¯}{11}\right)$ surfaces indicate that In has a substantial effect on the relative energies of formation of these surfaces. Indium-induced changes in the surface energetics enable the formation of inverted hexagonal pyramid defects having $\left(101\mathrm{}̱1\right)$ facets at the termination of threading defects on the (0001) surface of pseudomorphic ${\mathrm{In}}_x{\mathrm{Ga}}_{1-x}\mathrm{N}$ films. For dislocations terminating on the ${\mathrm{In}}_x{\mathrm{Ga}}_{1-x}\mathrm{N}\left(0001\mathrm{}̱\right)$ surface, the calculations predict that large $\left(10\mathrm{}\underset{¯}{11}\right)$ faceted defects are not energetically favorable.

• Received 1 June 1999

DOI:https://doi.org/10.1103/PhysRevB.60.R8473