Phonons in Potassium-doped Graphene: The Effects of Electron-phonon Interactions, Dimensionality, and Adatom Ordering
Graphene phonons are measured as a function of electron doping via the addition of potassium adatoms. In the low doping regime, the in-plane carbon G peak hardens and narrows with increasing doping, analogous to the trend seen in graphene doped via the field effect. At high dopings, beyond those accessible by the field effect, the G peak strongly softens and broadens. This is interpreted as a dynamic, nonadiabatic renormalization of the phonon self-energy. At dopings between the light and heavily doped regimes, we find a robust inhomogeneous phase where the potassium coverage is segregated into regions of high and low density. The phonon energies, linewidths, and tunability are notably very similar for one- to four-layer potassium-doped graphene, but significantly different to bulk potassium-doped graphite.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE SC OFFICE OF SCIENCE (SC)
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 1043379
- Report Number(s):
- BNL-96940-2012-JA; R&D Project: PO-011; KC0202010; TRN: US1203126
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 84, Issue 24; ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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