Optical conductivity, Drude weight and plasmons in twisted graphene bilayers
Entity
UAM. Departamento de Física de la Materia CondensadaPublisher
IOP PublishingDate
2013-11-01Citation
10.1088/1367-2630/15/11/113050
New Journal of Physics 15. (2013): 113050
ISSN
1367-2630 (print)DOI
10.1088/1367-2630/15/11/113050Funded by
This work has been supported by FCT under grants PTDC/FIS/101434/2008; PTDC/FIS/113199/2009, by MIC-Spain under grant FIS2010-21883-C02-02, FIS2011-23713 and FIS2012-33521, and by the European Research Council Advanced grant, contract 290846Project
info:eu-repo/grantAgreement/EC/FP7/290846Editor's Version
http://dx.doi.org/10.1088/1367-2630/15/11/113050Subjects
Tight binding model; Band structure; Graphene; Dielectric function; Random phase approximation; Plasmons; Dispersion relations; Rhenium; Optical absorption; FísicaRights
© IOP Publishing Ltd and Deutsche Physikalische GesellschaftAbstract
We numerically calculate the optical conductivity of twisted graphene bilayers within the continuum model. To obtain the imaginary part, we employ the regularized Kramers–Kronig relation, allowing us to discuss arbitrary twist angles, chemical potential and temperature. We find that the Drude weight D as a function of the chemical potential μ closely follows the shell structure of a twisted bilayer displayed by the density of states. For certain angles, this results in a transport gap D = 0 at finite μ. We also discuss the loss function
which, for low doping, is characterized by acoustic interband ‘plasmons’ and transitions close to the van Hove singularities. For larger doping, the plasmon mode of a decoupled graphene bilayer is recovered that is damped especially for small wave numbers
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Google Scholar:Stauber, Tobias
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San-Jose, Pablo
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Brey, Luis
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