Excitonic resonances as fingerprint of strong Coulomb coupling in graphene

T. Stroucken, J. H. Grönqvist, S. W. Koch

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

Within a self-consistent microscopic theory, the conditions for the existence of a strongly Coulomb-correlated phase in graphene is explored, and its fingerprints in the optical spectra are investigated. A second-order semimetal-to-insulator transition is predicted if the effective fine-structure constant exceeds the critical value 1/2. Above this value, the Coulomb interaction opens a gap in the quasiparticle spectrum that increases rapidly with increasing coupling strength. Energetically below the gap, the optical spectra are predicted to exhibit pronounced excitonic resonances that are superimposed on the Drude-like response of the filled graphene p-band. Experimental observation of these excitons could serve as a fingerprint for the existence of the Coulomb-correlated phase. Increasing the coupling constant results in a blueshift and increasing oscillator strength of the dominant resonance.

Original languageEnglish (US)
Pages (from-to)A86-A94
JournalJournal of the Optical Society of America B: Optical Physics
Volume29
Issue number2
DOIs
StatePublished - Feb 1 2012

ASJC Scopus subject areas

  • Statistical and Nonlinear Physics
  • Atomic and Molecular Physics, and Optics

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