Nonadiabatic phonons within the doped graphene layers of XC6 compounds

作者:Dean Mark P M*; Howard Christopher A; Saxena Siddharth S; Ellerby Mark
来源:Physical Review B, 2010, 81(4): 045405.
DOI:10.1103/PhysRevB.81.045405

摘要

We report Raman-scattering measurements of BaC6, SrC6, YbC6, and CaC6, which permit a systematic study of the phonons and the electron-phonon interaction within the doped graphene layers of these compounds. The out-of-plane carbon phonon softens as the spacing of the graphene layers is reduced in the series BaC6, SrC6, YbC6, and CaC6. This is due to increasing charge in the pi* electronic band. Electron-phonon interaction effects between the in-plane carbon modes at approximate to 1500 cm(-1) and the pi* electrons cause a strong nonadiabatic renormalization. As charge is transferred into the pi* band, these nonadiabatic effects are found to increase concurrent with a reduction in the phonon lifetime.

  • 出版日期2010-1