First-principles study of oxygenated diamond (001) surfaces with and without hydrogen

The structural characterization of oxygenated diamond (001) surface with and without H-presence has been investigated by the density-functional theory within the generalized gradient approximation and the plane-wave pseudopotential method. It is shown that, without the H, the O-bridge site has lower energy than the O-on-top site for both half and fully monolayer (ML) oxygen coverage. For hydrogenated diamond (001) surfaces, we found for half ML O coverage, a more stable (2 x 2):0.5H&0.5(OH) phase than the previously reported (2 x 1):0.5H&0.5(OH) phase [H. Tamura, H. Zhou, K. Sugisako, Y. Yokoi, S. Takami, M. Kubo, K. Teraishi, A. Miyamoto, A. Imamura, M.N. Gamo, T. Ando, Phys. Rev. B 61 (2000) 11025]. Furthermore, at one ML O coverage, a (2 x 2):(OH) phase is the most stable structure than the previously reported (2 x 1):(OH) phase. With the increase of the (OH) coverage, the importance of the hydrogen bonds increases in terms of stabilizing these structures. (c) 2006 Elsevier B.V. All rights reserved.