Coherent radial-breathing-like phonons in graphene nanoribbons

G. D. Sanders, A. R.T. Nugraha, R. Saito, C. J. Stanton

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)

Abstract

We have developed a microscopic theory for the generation and detection of coherent phonons in armchair and zigzag graphene nanoribbons using an extended tight-binding model for the electronic states and a valence force field model for the phonons. The coherent phonon amplitudes satisfy a driven oscillator equation with the driving term depending on photoexcited carrier density. We examine the coherent phonon radial-breathing-like mode amplitudes as a function of excitation energies and nanoribbon types. For photoexcitation near the optical absorption edge the coherent phonon driving term for the radial-breathing-like mode is much larger for zigzag nanoribbons where transitions between localized edge states provide the dominant contribution to the coherent phonon driving term. Using an effective mass theory, we explain how the armchair nanoribbon width changes in response to laser excitation.

Original languageEnglish
Article number205401
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume85
Issue number20
DOIs
Publication statusPublished - 2012 May 2

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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