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arXiv · 0712.2897

Origins of anomalous electronic structures of epitaxial graphene on silicon carbide

Seungchul Kim·Jisoon Ihm·Hyoung Joon Choi·Young-Woo Son
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Abstract

On the basis of first-principles calculations, we report that a novel interfacial atomic structure occurs between graphene and the surface of silicon carbide, destroying the Dirac point of graphene and opening a substantial energy gap there. In the calculated atomic structures, a quasi-periodic $6\times 6$ domain pattern emerges out of a larger commensurate $6\sqrt{3}\times6\sqrt{3}R30^\circ$ periodic interfacial reconstruction, resolving a long standing experimental controversy on the periodicity of the interfacial superstructures. Our theoretical energy spectrum shows a gap and midgap states at the Dirac point of graphene, which are in excellent agreement with the recently-observed anomalous angle-resolved photoemission spectra. Beyond solving unexplained issues of epitaxial graphene, our atomistic study may provide a way to engineer the energy gaps of graphene on substrates.

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Seungchul Kim, Jisoon Ihm, Hyoung Joon Choi, Young-Woo Son. 2008-04-29. Origins of anomalous electronic structures of epitaxial graphene on silicon carbide. https://doi.org/10.1103/physrevlett.100.176802

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