Absence of a metallic phase in charge-neutral graphene with a random gap

It is known that fluctuations in the electrostatic potential allow for metallic conduction (nonzero conductivity in the limit of an infinite system) if the carriers form a single species of massless two-dimensional Dirac fermions. A nonzero uniform mass \(\bar{M}\) opens up an excitation gap, locali...

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Bibliographic Details
Published inarXiv.org
Main Authors Bardarson, J H, Medvedyeva, M V, Tworzydlo, J, Akhmerov, A R, Beenakker, C W J
Format Paper Journal Article
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 04.02.2010
Subjects
Fermions
Graphene
Mathematical models
Physics - Mesoscale and Nanoscale Physics
Variations
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Summary:It is known that fluctuations in the electrostatic potential allow for metallic conduction (nonzero conductivity in the limit of an infinite system) if the carriers form a single species of massless two-dimensional Dirac fermions. A nonzero uniform mass \(\bar{M}\) opens up an excitation gap, localizing all states at the Dirac point of charge neutrality. Here we investigate numerically whether fluctuations \(\delta M \gg \bar{M} \neq 0\) in the mass can have a similar effect as potential fluctuations, allowing for metallic conduction at the Dirac point. Our negative conclusion confirms earlier expectations, but does not support the recently predicted metallic phase in a random-gap model of graphene.
ISSN:2331-8422
DOI:10.48550/arxiv.1002.0817