Reconstructed structures of the GaN and ZnO(10•1) anion semipolar surfaces were studied using density functional theory calculations. The twofold-coordinated anion atoms on the unreconstructed surfaces form anion dimers with reduced surface hole density. The residual holes on the dimerized surfaces were additionally compensated by formation of a dimer vacancy in every four 2x1 cells on GaN(10•1) and in two 2x1 cells on ZnO(10•1). The electrostatically stable 4x2 dimer vacancy reconstruction on the GaN(10•1) surface was found to be more stable than the previously suggested structures, and the 2x2 dimer vacancy reconstruction on the ZnO(10•1) surface explains the transmission electron microscopy observations.

Dimer-Vacancy Reconstructions of the GaN and ZnO(10¯11) Surfaces: Density Functional Theory Calculations. Lee, W.J., Kim, Y.S.: Physical Review B, 2011, 84[11], 115318