Using density-functional theory and a tight-binding approach we investigate the physical origin of distinct favourable geometries of adsorbed hydrogen atoms in various graphyne structures, and the relation with electronic properties. In particular, H atoms are adsorbed in-plane for α-graphyne, and they assume an oblique configuration in all other graphynes, including 6,6,12-graphyne. The origin of different configurations is identified by means of a simple tight-binding model and it is controlled by the tuning of the hopping between sp2-bonded C atoms and sp-bonded C atoms hybridized with the H atoms. We discuss in details how the geometry change of the attached H atom tunes the electronic properties like energy gap.
@article{arxiv.1402.1372,
title = {Density-Functional Theory and Tight-Binding Studies of the Geometry of Hydrogen Adsorbed on Graphynes},
author = {Hunpyo Lee and Jahyun Koo and Massimo Capone and Yongkyung Kwon and Hoonkyung Lee},
journal= {arXiv preprint arXiv:1402.1372},
year = {2014}
}