Velocity renormalization and anomalous quasiparticle dispersion in extrinsic graphene

S. Das Sarma and E. H. Hwang
Phys. Rev. B 87, 045425 – Published 28 January 2013

Abstract

Using many-body diagrammatic perturbation theory we consider carrier density- and substrate-dependent many-body renormalization of doped or gated graphene induced by Coulombic electron-electron interaction effects. We quantitatively calculate the many-body spectral function, the renormalized quasiparticle energy dispersion, and the renormalized graphene velocity using the leading-order self-energy in the dynamically screened Coulomb interaction within the ring diagram approximation. We predict experimentally detectable many-body signatures, which are enhanced as the carrier density and the substrate dielectric constant are reduced, finding an intriguing instability in the graphene excitation spectrum at low wave vectors where interaction completely destroys all particlelike features of the noninteracting linear dispersion. We also make experimentally relevant quantitative predictions about the carrier density and wave-vector dependence of graphene velocity renormalization induced by electron-electron interaction. We compare on-shell and off-shell self-energy approximations within the ring diagram approximation, finding a substantial quantitative difference between their predicted velocity renormalization corrections in spite of the generally weak-coupling nature of interaction in graphene.

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  • Received 15 March 2012

DOI:https://doi.org/10.1103/PhysRevB.87.045425

©2013 American Physical Society

Authors & Affiliations

S. Das Sarma1 and E. H. Hwang1,2

  • 1Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park, Maryland 20742-4111
  • 2SKKU Advanced Institute of Nanotechnology, Sungkyunkwan University, Suwon 440-746, Korea

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Issue

Vol. 87, Iss. 4 — 15 January 2013

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