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Many-body effects in doped graphene layers

Speaker: 
Giovanni Vignale
Date: 
Wed, 09/07/2014 - 11:00am to 12:00pm
Location: 
S13-M01-11 (Physics Conference Room)
Host: 
Antonio Castro Neto
Event Type: 
Seminars

The peculiar band structure of graphene, coupled with electron-electron interactions, is responsible for the breakdown of the Fermi liquid concept in the undoped material.  Interesting many-body effects are also predicted to occur in  doped graphene layers, where the Fermi liquid picture still applies with an enhanced Fermi velocity.  In this talk  I review some of these effects, which should be observable in optical and infrared spectroscopies, magnetic susceptibility measurement, and thermal transport measurements.    Due to the lack of Galilean invariance, both the plasmon frequency and  the Drude weight in the optical conductivity are significantly enhanced relative to the conventional  RPA values.  The orbital magnetic susceptibility, which vanishes in the free-electron approximation, is found to be positive, i.e. paramagnetic, with a value that is completely controlled by the electron-electron interaction.   The quasiparticle lifetime is long and leads to a large electronic component of the thermal conductivity, which strongly violates the Wiedemann-Franz law.  I review these  theoretical predictions vis-a-vis the current state of the experiment.

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