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arXiv · 1112.2532

Large Bandgap Opening Between Graphene Dirac Cones Induced by Na Adsorption onto an Ir Superlattice

Marco Papagno·Stefano Rusponi·Polina Makarovna Sheverdyaeva·Sergio Vlaic·Markus Etzkorn·Daniela Pacilé·Paolo Moras·Carlo Carbone·Harald Brune
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Abstract

We investigate the effects of Na adsorption on the electronic structure of bare and Ir cluster superlattice covered epitaxial graphene on Ir(111) using angle-resolved photoemission spectroscopy and scanning tunneling microscopy. At Na saturation coverage a massive charge migration from sodium atoms to graphene raises the graphene Fermi level by about 1.4 eV relative to its neutrality point. We find that Na is adsorbed on top of the graphene layer and when coadsorbed onto an Ir cluster superlattice it results in the opening of a large bandgap of Δ = 740 meV comparable to the one of Ge and with preserved high group velocity of the charge carriers.

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Marco Papagno, Stefano Rusponi, Polina Makarovna Sheverdyaeva, Sergio Vlaic, Markus Etzkorn, Daniela Pacilé, Paolo Moras, Carlo Carbone, Harald Brune. 2011-12-12. Large Bandgap Opening Between Graphene Dirac Cones Induced by Na Adsorption onto an Ir Superlattice. https://doi.org/10.1021/nn203841q

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