DUV Double-Resonant Raman Spectra and Interference Effect in Graphene: First-Principles Calculations
Journal
Journal of Raman Spectroscopy
Journal Volume
56
Journal Issue
4
Start Page
316
End Page
323
ISSN
10974555
03770486
Date Issued
2025
Author(s)
Abstract
We calculate double-resonance Raman (DRR) spectra of monolayer graphene by first-principles density functional calculation, for wide laser excitation energies from the near-infrared (1.58 eV) to the deep-ultraviolet (DUV, 5.41 eV) region. When laser excitation energy, (Formula presented.), goes into the DUV region, Raman peak wavenumber for G (Formula presented.) band switches from red-shift to blue-shift and for 2D (Formula presented.) band switches from red-shift to constant, in contrast to the continuous blue-shift of G (Formula presented.) band. Raman intensity of the three bands generally decreases with increasing (Formula presented.), except for (Formula presented.) around 4.08 eV where Raman intensity diverges due to van Hove singularity of electron density of states. The combined two-phonon modes change with (Formula presented.) for both G (Formula presented.) and G (Formula presented.) bands (e.g., from 2LO to 2TO and back to 2LO for G (Formula presented.) and from LA + LO/TO to TA + LO/TO for G (Formula presented.)) but remain 2LO for 2D (Formula presented.) band. Further, the dominant DRR scattering process of G (Formula presented.) band changes from the electron-hole ((Formula presented.) or (Formula presented.)) scattering processes to the (Formula presented.) scattering processes as (Formula presented.) goes into the DUV region, since the Dirac energy bands become asymmetric between (Formula presented.) and (Formula presented.) band that suppresses the (Formula presented.) process and the Raman intensity. Another factor to suppress the Raman intensity is the quantum interference effect between four scattering processes ((Formula presented.)) which changes from constructive to destructive interference and finally to no interference with increasing (Formula presented.). We calculate (Formula presented.) -dependent Raman tensor of the three bands and polarized Raman spectra, which further support the interference effect. The calculated results are directly compared and consistent with the experimental results.
Subjects
Blue Shift
Electron Density Measurement
Electron Scattering
Excitation Energy
Quantum Interference Devices
Raman Scattering
Red Shift
Deep Ultraviolet
Deep-ultraviolet Regions
Double Resonance
Energy
Graphenes
Interference Effects
Raman Intensities
Red Shift
Scattering Process
Laser Excitation
SDGs
Publisher
John Wiley and Sons Ltd
Type
journal article