Direction-Controlled Chemical Doping for Reversible G-Phonon Mixing in ABC Trilayer Graphene
arXiv:2008.03001 · doi:10.1038/srep08707
Abstract
Not only the apparent atomic arrangement but the charge distribution also defines the crystalline symmetry that dictates the electronic and vibrational structures. In this work, we report reversible and direction-controlled chemical doping that modifies the inversion symmetry of AB-bilayer and ABCtrilayer graphene. For the top-down and bottom-up hole injection into graphene sheets, we employed molecular adsorption of electronegative I2 and annealing-induced interfacial hole doping, respectively. The chemical breakdown of the inversion symmetry led to the mixing of the G phonons, Raman active Eg and Raman-inactive Eu modes, which was manifested as the two split G peaks, G- and G+. The broken inversion symmetry could be recovered by removing the hole dopants by simple rinsing or interfacial molecular replacement. Alternatively, the symmetry could be regained by double-side charge injection, which eliminated G- and formed an additional peak, Go, originating from the barely doped interior layer. Chemical modification of crystalline symmetry as demonstrated in the current study can be applied to other low dimensional crystals in tuning their various material properties.
20 pages, 6 figures
References in corpus (15)
- Electric Field Effect in Atomically Thin Carbon Films
- The electronic properties of graphene
- Graphene plasmonics
- Intrinsic and Extrinsic Performance Limits of Graphene Devices on SiO2
- Hunting for Monolayer Boron Nitride: Optical and Raman Signatures
- Optical Separation of Mechanical Strain from Charge Doping in Graphene
- Dependence of band structures on stacking and field in layered graphene
- Phonon dispersions and vibrational properties of monolayer, bilayer, and trilayer graphene
- Charge distribution and screening in layered graphene systems
- Observation of Distinct Electron-Phonon Couplings in Gated Bilayer Graphene
- Two-Dimensional Water Diffusion at a Graphene-Silica Interface
- Adsorption of diatomic halogen molecules on graphene: A van der Waals density functional study
- Observation of Raman G-band splitting in top-doped few-layer graphene
- Electron-Phonon Interactions for Optical Phonon Modes in Few-Layer Graphene
- Bromination of Graphene and Graphite