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arXiv · 1002.4117

Role of the self-interaction error in studying chemisorption on graphene from first-principles

Simone Casolo·Espen Flage-Larsen·Ole Martin Løvvik·George R. Darling·Gian Franco Tantardini
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Abstract

Adsorption of gaseous species, and in particular of hydrogen atoms, on graphene is an important process for the chemistry of this material. At the equilibrium geometry, the H atom is covalently bonded to a carbon that puckers out from the surface plane. Nevertheless the \emph{flat} graphene geometry becomes important when considering the full sticking dynamics. Here we show how GGA-DFT predicts a wrong spin state for this geometry, namely $S_z$=0 for a single H atom on graphene. We show how this is caused by the self-interaction error since the system shows fractional electron occupations in the two bands closest to the Fermi energy. It is demonstrated how the use of hybrid functionals or the GGA+$U$ method an be used to retrieve the correct spin solution although the latter gives an incorrect potential energy curve.

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Simone Casolo, Espen Flage-Larsen, Ole Martin Løvvik, George R. Darling, Gian Franco Tantardini. 2010-02-22. Role of the self-interaction error in studying chemisorption on graphene from first-principles. https://doi.org/10.1103/physrevb.81.205412

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