Friday, June 21, 2013

1306.4716 (John F. Dobson et al.)

How many-body effects modify the van der Waals interaction between
graphene sheets

John F. Dobson, Tim Gould, Giovanni Vignale
Undoped graphene sheets at low temperatures have previously been predicted, via Random Phase Approximation (RPA) calculations, to exhibit unusual van der Waals interactions. Here we investigate the modifications to these interactions resulting from the inclusion of terms beyond the RPA in the density response of a graphene sheet. For asymptotically large separations, $D\rightarrow\infty$, the interaction is found to be substantially reduced from the RPA prediction. Its qualitative behavior depends strongly on the form of the many-body enhancement of the velocity of the massless Dirac fermions and may provide independent confirmation of the latter.
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