Molecular ordering of glycine on Cu(100): The p(2×4) superstructure.

Glycine molecules deposited on a Cu(100) surface give rise to an anisotropic free-electron-like (FEL) electronic dispersion in its p(2×4) superstructure, as reported in recent experiments [ K. Kanazawa et al. Phys. Rev. Lett. 99 216102 (2007); J. Am. Chem. Soc. 129 740 (2007)]. Using density functional theory and exhaustively calculating sixteen possible structures, we have determined the molecular arrangement that can give the experimentally observed FEL behavior. Eight configurations, among the sixteen, were not investigated before in the literature and one of them (denoted Str-3) is able to provide the FEL behavior in excellent agreement with the experiments. In addition, the particular configuration Str-3 satisfies other criteria of the observed p(2×4) superstructure, e.g., chirality and cleavable orientation. [ABSTRACT FROM AUTHOR]