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arXiv · 0910.2407

Symmetry-induced gap opening in graphene superlattices

Rocco Martinazzo·Simone Casolo·Gian Franco Tantardini
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Abstract

We study nxn honeycomb superlattices of defects in graphene. The considered defects are missing p_z orbitals and can be realized by either introducing C atom vacancies or chemically binding simple atomic species at the given sites. Using symmetry arguments we show how it is possible to open a gap when n=3m+1,3m+2 (m integer), and estimate its value to have an approximate square-root dependence on the defect concentration x=1/n^2. Tight-binding calculations confirm these findings and show that the induced-gaps can be quite large, e.g. ~100 meV for x~10^{-3}. Gradient-corrected density functional theory calculations on a number of superlattices made by H atoms adsorbed on graphene are in good agreement with tight-binding results, thereby suggesting that the proposed structures may be used in practice to open a gap in graphene.

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Rocco Martinazzo, Simone Casolo, Gian Franco Tantardini. 2009-10-13. Symmetry-induced gap opening in graphene superlattices. https://doi.org/10.1103/physrevb.81.245420

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