Structure of the hydrogen stabilized MgO(111)-(1 · 1) surface from low energy electron diffraction (LEED)

A structural study has been performed on the MgO(111)-(1 · 1) surface by low energy electron diffraction (LEED) using experimental data obtained with a delay-line-detector LEED (DLD-LEED) system to minimize electron damage. It was found that the surface is terminated by a hydroxide layer with the topO–Mg interlayer spacing equal to 1.02 Å, which is close to the spacings betweenMg andO planes in bulk brucite crystals (Mg(OH)2). This is in good agreement with a recent study using photoelectron diffraction (PhD) spectroscopy and density functional theory calculation (DFT) [V.K. Lazarov, R. Plass, H.-C. Poon, D.K. Saldin,M.Weinert, S.A. Chambers,M. GajdardziskaJosifovska, Phys. Rev. B 71 (2005) 115434]. The second interlayer spacing shows a small expansion of 3% and the third is bulk-like, while the DFT calculation predicted that the spacings below the top one are all bulk-like. This result clearly favors hydroxylation [K. Refson, R.A. Wogelius, D.G. Fraser, M.C. Payne, M.H. Lee, V. Milman, Phys. Rev. B 52 (1995) 10823] as a way of stabilizing the MgO(111) surface at low temperature overmetallization, which has a top layer spacing of 0.86 Å forO termination and 1.25 Å forMg termination [Lazarov et al. 2005; T. Tsukada, T. Hoshino, Phys. Soc. Jpn. 51 (1982) 2562, J. Goniakowski, C. Noguera, Phys. Rev. B 60 (1999) 16120]. 2006 Elsevier B.V. All rights reserved.