  The coalescence in dense arrays of spontaneously formed GaN nanowires
proceeds by bundling: adjacent nanowires bend and merge at their top, thus
reducing their surface energy at the expense of the elastic energy of bending.
We give a theoretical description of the energetics of this bundling process.
The bending energy is shown to be substantially reduced by the creation of
dislocations at the coalescence joints. A comparison of experimental and
calculated x-ray diffraction profiles from ensembles of bundled nanowires
demonstrates that a large part of the bending energy is indeed relaxed by
plastic deformation. The residual bending manifests itself by extended tails of
the diffraction profiles.
