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Related papers: Magnetophonon resonance in graphite: High-field Ra…

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The micro-Raman scattering response of a graphene-like location on the surface of bulk natural graphite is investigated both at $T=\unit{4.2}{K}$ and at room temperature in magnetic fields up to 29 T. Two different polarization…

Mesoscale and Nanoscale Physics · Physics 2014-10-03 M. Kuhne , C. Faugeras , P. Kossacki , A. A. L. Nicolet , M. Orlita , Yu. I. Latyshev , M. Potemski

We present a detailed calculation of intensities of two-phonon and four-phonon Raman peaks in graphene. Writing the low-energy hamiltonian of the interaction of electrons with the crystal vibrations and the electromagnetic field from pure…

Materials Science · Physics 2009-11-13 D. M. Basko

We have investigated the effects of ozone treatment on graphene by Raman scattering. Sequential ozone short-exposure cycles resulted in increasing the $p$ doping levels as inferred from the blue shift of the 2$D$ and $G$ peak frequencies,…

Mesoscale and Nanoscale Physics · Physics 2015-05-19 F. Alzina , H. Tao , J. Moser , Y. Garcia , A. Bachtold , C. M. Sotomayor-Torres

We show that the electron-phonon coupling in graphene, in contrast with the non-relativistic two-dimensional electron gas, leads to shifts in the phonon frequencies that are non-trivial functions of the electronic density. These shifts can…

Strongly Correlated Electrons · Physics 2013-05-29 A. H. Castro Neto , Francisco Guinea

Raman spectroscopy is a fast, non-destructive means to characterize graphene samples. In particular, the Raman spectra show a significant dependence on doping. While the change in position and width of the G peak can be explained by the…

Materials Science · Physics 2015-05-13 D. M. Basko , S. Piscanec , A. C. Ferrari

A Raman study of a back gated bilayer graphene sample is presented. The changes in the Fermi level induced by charge transfer splits the Raman G-band, hardening its higher component and softening the lower one. These two components are…

Mesoscale and Nanoscale Physics · Physics 2008-12-16 L. M. Malard , D. C. Elias , E. S. Alves , M. A. Pimenta

We report a Raman spectroscopy study of graphene field-effect transistors (GFET) with a controlled amount of defects introduced in graphene by exposure to electron-beam irradiation. Raman spectra are taken at T = 8 K over a range of back…

Materials Science · Physics 2015-06-22 Isaac Childres , Luis A. Jauregui , Yong P. Chen

An experimental study of Raman scattering in N-layer graphene as a function of the top layer doping is reported. At high doping level, achieved by a CHF_3 plasma treatment, we observe a splitting of the $G$ band in the spectra of bilayer…

Mesoscale and Nanoscale Physics · Physics 2010-03-23 M. Bruna , S. Borini

The scattering of lattice excitations (phonons) with the photoexcited charge carriers is of a major concern in optoelectronic devices. Here, the resonant Raman scattering will be utilized to study an exciton-phonon interaction in GaN…

Polarization resolved, Raman scattering response due to E$_{2g}$ phonon in monolayer graphene has been investigated in magnetic fields up to 29 T. The hybridization of the E$_{2g}$ phonon with only the fundamental inter Landau level…

Mesoscale and Nanoscale Physics · Physics 2013-01-01 P. Kossacki , C. Faugeras , M. Kühne , M. Orlita , A. Mahmood , E. Dujardin , R. R. Nair , A. K. Geim , M. Potemski

We use first-principles density-functional calculations to determine the frequency shift of the A$'_1$-${\bf K}$ phonon (Raman D band) in monolayer graphene, as a function of the charge doping. A detailed DFT study on the electron-phonon…

Materials Science · Physics 2007-05-23 Srijan Kumar Saha , U. V. Waghmare , H. R. Krishnamurthy , A. K. Sood

The phonon dispersion of graphene on Ir(111) has been determined by means of angle-resolved inelastic electron scattering and density functional calculations. Kohn anomalies of the highest optical-phonon branches are observed at the…

Materials Science · Physics 2015-06-17 M. Endlich , A. Molina-Sánchez , L. Wirtz , J. Kröger

Time dynamics of photoexcited electron-hole pairs is important for a number of technologies, in particular solar cells. We combined ultrafast pump-probe Raman scattering and photoemission to directly follow electron-hole excitations as well…

Mesoscale and Nanoscale Physics · Physics 2017-01-26 Jhih-An Yang , Stephen Parham , Daniel Dessau , Dmitry Reznik

We present a comparative measurement of the G-peak oscillations of phonon frequency, Raman intensity and linewidth in the Magneto-Raman scattering of optical E2g phonons in mechanically exfoliated ABA- and ABC-stacked trilayer graphene…

We present a systematic study of the Raman spectra of optical phonons in graphene monolayers under tunable uniaxial tensile stress. Both the G and 2D bands exhibit significant red shifts. The G band splits into two distinct sub-bands (G+,…

Materials Science · Physics 2008-12-15 Mingyuan Huang , Hugen Yan , Changyao Chen , Daohua Song , Tony F. Heinz , James Hone

Radio-frequency compressed ultrafast electron diffraction has been used to probe the coherent and incoherent coupling of impulsive electronic excitation at 1.55 eV (800 nm) to optical and acoustic phonon modes directly from the perspective…

Materials Science · Physics 2015-06-23 Robert P. Chatelain , Vance R. Morrison , Bart L. M. Klarenaar , Bradley J. Siwick

We report the observation of an intense anomalous peak at 1608 cm$^{-1}$ in the Raman spectrum of graphene associated to the presence of chromium nanoparticles in contact with graphene. Bombardment with an electron beam demonstrates that…

Photoemission studies of graphene have resulted in a long-standing controversy concerning the strength of the experimental electron-phonon interaction in comparison with theoretical calculations. Using high-resolution angle-resolved…

Materials Science · Physics 2015-05-30 David A. Siegel , Choongyu Hwang , Alexi V. Fedorov , Alessandra Lanzara

We determine the nature of coupled phonons and magnetic excitations in AlFeO3 using inelastic light scattering from 5 K to 315 K covering a spectral range from 100-2200 cm-1 and complementary first-principles density functional theory-based…

Strongly Correlated Electrons · Physics 2012-05-01 Pradeep Kumar , A. Bera , D. V. S. Muthu , S. N. Shirodkar , R. Saha , A. Shireen , A. Sundaresan , U. V. Waghmare , A. K. Sood , C. N. R. Rao

We report the ultrafast dynamics of the 47.4 THz coherent phonons of graphite interacting with a photoinduced non-equilibrium electron-hole plasma. Unlike conventional materials, upon photoexcitation the phonon frequency of graphite…

Other Condensed Matter · Physics 2008-03-13 Kunie Ishioka , Muneaki Hase , Masahiro Kitajima , Ludger Wirtz , Angel Rubio , Hrvoje Petek