Signature of the two-dimensional phonon dispersion in graphene probed by double-resonant Raman scattering

May, Patrick; Lazzeri, Michele; Venezuela, P.; Herziger, Felix; Callsen, Gordon; Reparaz, J. S.; Hoffmann, A.; Mauri, Francesco; Maultzsch, Janina

doi:10.1103/physrevb.87.075402

Cited by 66 publications

(66 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, for shorter resonant phonon wave-vectors, i.e., larger excitation energies, a larger frequency range can be accessed, leading to a broadening of this Raman mode. Similar observations, both theoretically and experimentally, were made for the D+D mode at approximately 2450 cm −1 in the Raman spectrum of single-layer graphene 24 . The comparison of our measured D -mode spectra with calculations from Venezuela et al (compare Ref.…”

Section: Resultssupporting

confidence: 82%

“…Therefore, we can assign this scattering process to so-called 'inner' processes, i.e., the electronic transition must be between K and M . The importance of inner processes was discussed extensively in recent literature on double-resonances in graphene 20,24 , showing that the formerly proposed restriction to only 'outer' processes is incorrect 38 . Our results furthermore enable us to map the LA phonon branch along the Γ − K high-symmetry direction.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Double-resonant LA phonon scattering in defective graphene and carbon nanotubes

et al. 2014

Self Cite

View full text Add to dashboard Cite

We present measurements of the D Raman mode in graphene and carbon nanotubes at different laser excitation energies. The Raman mode around 1050 -1150 cm −1 originates from a doubleresonant scattering process of longitudinal acoustic (LA) phonons with defects. We investigate its dependence on laser excitation energy, on the number of graphene layers and on the carbon nanotube diameter. We assign this Raman mode to so-called 'inner' processes with resonant phonons mainly from the Γ−K high-symmetry direction. The asymmetry of the D mode is explained by additional contributions from phonons next to the Γ − K line. Our results demonstrate the importance of inner contributions in the double-resonance scattering process and add a fast method to investigate acoustic phonons in graphene and carbon nanotubes by optical spectroscopy.

show abstract

Section: Resultssupporting

confidence: 82%

Section: Resultsmentioning

confidence: 99%

Double-resonant LA phonon scattering in defective graphene and carbon nanotubes

et al. 2014

Self Cite

View full text Add to dashboard Cite

show abstract

“…The D + D peak lies at ∼2450 cm −1 , and it is a combination between D and the D peak at ∼1100 cm −1 . 42,[105][106][107][108][109] The relative areas of these peaks shows a peculiar dependence on excitation energy: A(2D )/A(2D) decreases for increasing excitation energy, while A(D + D )/A(2D) increases, see Fig. 14. This further confirms the importance of resonant processes on the two-phonon lines area.…”

Section: Eq (12) We Get Dsmentioning

confidence: 95%

Raman scattering efficiency of graphene

et al. 2013

View full text Add to dashboard Cite

We determine the Raman scattering efficiency of the G and 2D peaks in graphene. Three substrates are used: silicon covered with 300 or 90 nm oxide, and calcium fluoride (CaF 2). On Si/SiO x , the areas of the G and 2D peak show a strong dependence on the substrate due to interference effects, while on CaF 2 no significant dependence is detected. Unintentional doping is reduced by placing graphene on CaF 2. We determine the Raman scattering efficiency by comparison with the 322 cm −1 peak area of CaF 2. At 2.41 eV, the Raman efficiency of the G peak is ∼ 200 × 10 −5 m −1 Sr −1 , and changes with the excitation energy to the power of 4. The 2D Raman efficiency is at least one order of magnitude higher than that of the G peak, with a different excitation energy dependence.

show abstract

“…However, a discrepancy in the TO splitting between theory and experiment can be observed for q vectors close to K. The TO phonon splitting is largest along Γ-K and decreases away from this high-symmetry line. Since phonons away from the high-symmetry direction also contribute to the double resonance [34], the experimentally measured TO splitting is expected to be smaller than theoretically predicted along Γ-K. Thus, the theoretical curves should represent lower and upper limits for the experimental FIG.…”

mentioning

confidence: 86%

Two-Dimensional Analysis of the Double-Resonant 2D Raman Mode in Bilayer Graphene

et al. 2014

Self Cite

View full text Add to dashboard Cite

By computing the double-resonant Raman scattering cross section completely from first principles and including the electron-electron interaction at the GW level, we unravel the dominant contributions for the double-resonant 2D mode in bilayer graphene. We show that, in contrast to previous works, the so-called inner processes are dominant and that the 2D-mode line shape is described by three dominant resonances around the K point. We show that the splitting of the transversal optical (TO) phonon branch in the Γ-K direction, as large as 12 cm(-1) in the GW approximation, is of great importance for a thorough description of the 2D-mode line shape. Finally, we present a method to extract the TO phonon splitting and the splitting of the electronic bands from experimental data.

show abstract

Signature of the two-dimensional phonon dispersion in graphene probed by double-resonant Raman scattering

Cited by 66 publications

References 37 publications

Double-resonant LA phonon scattering in defective graphene and carbon nanotubes

Double-resonant LA phonon scattering in defective graphene and carbon nanotubes

Raman scattering efficiency of graphene

Two-Dimensional Analysis of the Double-Resonant 2D Raman Mode in Bilayer Graphene

Contact Info

Product

Resources

About