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arXiv · 1404.6132

High Crystallinity and Decoupling of Graphene on a Metal: Reduced Coulomb Screening and Tunable pn-Junctions

Søren Ulstrup·Mie Andersen·Marco Bianchi·Lucas Barreto·Bjørk Hammer·Liv Hornekær·Philip Hofmann
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Abstract

High quality epitaxial graphene films can be applied as templates for tailoring graphene-substrate interfaces that allow for precise control of the charge carrier behavior in graphene through doping and many-body effects. By combining scanning tunneling microscopy, angle-resolved photoemission spectroscopy and density functional theory we demonstrate that oxygen intercalated epitaxial graphene on Ir(111) has high structural quality, is quasi free-standing, and shows signatures of many-body interactions. Using this system as a template, we show that tunable pn-junctions can be patterned by adsorption and intercalation of rubidium, and that the n-doped graphene regions exhibit a reduced Coulomb screening via enhanced electron-plasmon coupling. These findings are central for understanding and tailoring the properties of graphene-metal contacts e.g. for realizing quantum tunneling devices.

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Søren Ulstrup, Mie Andersen, Marco Bianchi, Lucas Barreto, Bjørk Hammer, Liv Hornekær, Philip Hofmann. 2014-04-24. High Crystallinity and Decoupling of Graphene on a Metal: Reduced Coulomb Screening and Tunable pn-Junctions. https://arxiv.org/abs/1404.6132

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