We have studied phonon properties of graphene theoretically with different concentrations of 13C isotope and vacancy-type defects. The forced vibrational method, which is based on the mechanical resonance to extract the pure vibrational eigenmodes by numerical simulation, has been employed to compute the phonon density of states (PDOSs) and mode pattern of isotope-disordered graphene as well as a combined isotope and vacancy-type defective graphene structure. We observe a linear reduction of the E 2g mode frequencies with an increase in 13C concentration due to the reduced mass variation of the isotope mixture. We find a downshift of the E2g mode of 65 cm- 1, which is a very good agreement with the experimental results, and the phonon frequencies described by the simple harmonic oscillator model. The vacancy-type defects break down the phonon degeneracy at the ETH.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Mechanical Engineering
- Materials Chemistry
- Electrical and Electronic Engineering