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arXiv · 1011.0888

Evolution of Microscopic Localization in Graphene in a Magnetic Field from Scattering Resonances to Quantum Dots

Suyong Jung·Gregory M. Rutter·Nikolai N. Klimov·David B. Newell·Irene Calizo·Angela R. Hight-Walker·Nikolai B. Zhitenev·Joseph A. Stroscio
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Abstract

Graphene is a unique two-dimensional material with rich new physics and great promise for applications in electronic devices. Physical phenomena such as the half-integer quantum Hall effect and high carrier mobility are critically dependent on interactions with impurities/substrates and localization of Dirac fermions in realistic devices. We microscopically study these interactions using scanning tunneling spectroscopy (STS) of exfoliated graphene on a SiO2 substrate in an applied magnetic field. The magnetic field strongly affects the electronic behavior of the graphene; the states condense into welldefined Landau levels with a dramatic change in the character of localization. In zero magnetic field, we detect weakly localized states created by the substrate induced disorder potential. In strong magnetic field, the two-dimensional electron gas breaks into a network of interacting quantum dots formed at the potential hills and valleys of the disorder potential. Our results demonstrate how graphene properties are perturbed by the disorder potential; a finding that is essential for both the physics and applications of graphene.

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Suyong Jung, Gregory M. Rutter, Nikolai N. Klimov, David B. Newell, Irene Calizo, Angela R. Hight-Walker, Nikolai B. Zhitenev, Joseph A. Stroscio. 2010-11-03. Evolution of Microscopic Localization in Graphene in a Magnetic Field from Scattering Resonances to Quantum Dots. https://doi.org/10.1038/nphys1866

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