By using grazing-incidence X-ray diffraction methods, the p(2 x 2) surface structures of the monocrystalline (111) oxide and of a 5-monolayer thick (111) oxide film on Au(111) were both shown to exhibit the theoretically predicted octopolar reconstruction locally. On the other hand, the monocrystal exhibited a single Ni termination with double steps, while the thin film exhibited both possible terminations, (O and Ni) and single steps.

Atomic Structure of the Polar NiO(111)-p(2 x 2) Surface. A.Barbier, C.Mocuta, H.Kuhlenbeck, K.F.Peters, B.Richter, G.Renaud: Physical Review Letters, 2000, 84[13], 2897-900