Nonadiabatic Kohn Anomaly in a Doped Graphene Monolayer

Michele Lazzeri and Francesco Mauri
Phys. Rev. Lett. 97, 266407 – Published 29 December 2006

Abstract

We compute, from first principles, the frequency of the E2g, Γ phonon (Raman G band) of graphene, as a function of the charge doping. Calculations are done using (i) the adiabatic Born-Oppenheimer approximation and (ii) time-dependent perturbation theory to explore dynamic effects beyond this approximation. The two approaches provide very different results. While the adiabatic phonon frequency weakly depends on the doping, the dynamic one rapidly varies because of a Kohn anomaly. The adiabatic approximation is considered valid in most materials. Here, we show that doped graphene is a spectacular example where this approximation miserably fails.

  • Figure
  • Figure
  • Figure
  • Received 23 October 2006

DOI:https://doi.org/10.1103/PhysRevLett.97.266407

©2006 American Physical Society

Authors & Affiliations

Michele Lazzeri and Francesco Mauri

  • IMPMC, Universités Paris 6 et 7, CNRS, IPGP, 140 rue de Lourmel, 75015 Paris, France

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 97, Iss. 26 — 31 December 2006

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review Letters

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×