Molecular ordering of glycine on Cu(100): the p($2\times4$) superstructure

TL;DR

This study uses density functional theory to identify a molecular arrangement of glycine on Cu(100) that explains the experimentally observed anisotropic free-electron-like electronic dispersion in the p(2×4) superstructure.

Contribution

The paper identifies a new molecular configuration (Str-3) that matches experimental FEL behavior and satisfies structural criteria, expanding understanding of glycine on Cu(100).

Findings

Str-3 configuration reproduces FEL behavior accurately

Eight new configurations were explored, including Str-3

The identified structure matches experimental superstructure features

Abstract

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