Phonon self-energy corrections to non-zero wavevector phonon modes in single-layer graphene

Abstract

Phonon self-energy corrections have mostly been studied theoretically and experimentally for phonon modes with zone-center (q = 0) wave-vectors. Here, gate-modulated Raman scattering is used to study phonons of a single layer of graphene (1LG) in the frequency range from 2350 to 2750 cm-1, which shows the G* and the G'-band features originating from a double-resonant Raman process with q \not= 0. The observed phonon renormalization effects are different from what is observed for the zone-center q = 0 case. To explain our experimental findings, we explored the phonon self-energy for the phonons with non-zero wave-vectors (q \not= 0) in 1LG in which the frequencies and decay widths are expected to behave oppositely to the behavior observed in the corresponding zone-center q = 0 processes. Within this framework, we resolve the identification of the phonon modes contributing to the G* Raman feature at 2450 cm-1 to include the iTO+LA combination modes with q \not= 0 and the 2iTO overtone modes with q = 0, showing both to be associated with wave-vectors near the high symmetry point K in the Brillouin zone.

References in corpus (8)

• The electronic properties of graphene
• The structure of suspended graphene sheets
• Non-adiabatic Kohn-anomaly in a doped graphene monolayer
• Electron-Phonon Interactions in Graphene, Bilayer Graphene, and Graphite
• Observation of Anomalous Phonon Softening in Bilayer Graphene
• Observation of Distinct Electron-Phonon Couplings in Gated Bilayer Graphene
• Kohn Anomaly in Raman Spectroscopy of Single Wall Carbon Nanotubes
• Polaronic signatures and spectral properties of graphene antidot lattices

Cited by in corpus (3)

• Coherent Phonons in Carbon Nanotubes and Graphene
• Decay and Frequency Shift of Inter and Intravalley Phonons in Graphene -Dirac Cone Migration-
• Heavy doped ABA stacked trilayer graphene: triple splitting of its Raman G peak