Observation of Electron-Phonon Couplings and Fano Re-sonances in Epitaxial Bilayer Graphene
Author(s)
J. M. Baranowski,
M. Mozdzonek,
P. Dabrowski,
K. Grodecki*,
P. Osewski,
W. Kozlowski,
M. Kopciuszynski,
W. Strupinski
Affiliation(s)
Institute of Electronic Materials Technology, Warsaw, Poland;Faculty of Physics, University of Warsaw, Warsaw, Poland. Institute of Electronic Materials Technology, Warsaw, Poland. Faculty of Physics and Applied Informatics, Department of Solid State Physics, University of Lodz, Lodz, Poland. Institute of Physics, M. Curie-Sklodowska University, Lublin, Poland.
Institute of Electronic Materials Technology, Warsaw, Poland;Faculty of Physics, University of Warsaw, Warsaw, Poland. Institute of Electronic Materials Technology, Warsaw, Poland. Faculty of Physics and Applied Informatics, Department of Solid State Physics, University of Lodz, Lodz, Poland. Institute of Physics, M. Curie-Sklodowska University, Lublin, Poland.
ABSTRACT
The results of optical investigation of hydrogenated epitaxial bilayer graphene are presented. A softening and an increase of the intensity of the in-plane anti-symmetric phonon mode are observed at 0.2eV. It is suggested that they both originate from coupling of the optically active phonon mode to virtual electronic transitions, which is related to the band structure of bilayer graphene and leads to the “charged phonon” effect. In addition, it is noted that optically active phonon peaks have pronounced Fano shapelines. It is argued that the Fano shapeline is attributed to the interaction of the phonon mode with a continuum of electronic transitions in valence bands of hydrogenated bilayer graphene.
Cite this paper
J. M. Baranowski, M. Mozdzonek, P. Dabrowski, K. Grodecki, P. Osewski, W. Kozlowski, M. Kopciuszynski and W. Strupinski, "Observation of Electron-Phonon Couplings and Fano Re-sonances in Epitaxial Bilayer Graphene," Graphene, Vol. 2 No. 4, 2013, pp. 115-120. doi: 10.4236/graphene.2013.24017.
J. M. Baranowski, M. Mozdzonek, P. Dabrowski, K. Grodecki, P. Osewski, W. Kozlowski, M. Kopciuszynski and W. Strupinski, "Observation of Electron-Phonon Couplings and Fano Re-sonances in Epitaxial Bilayer Graphene," Graphene, Vol. 2 No. 4, 2013, pp. 115-120. doi: 10.4236/graphene.2013.24017.
References
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[1] T. Ando, “Anomaly of Optical Phonon in Monolayer Graphene,” Journal of the Physical Society of Japan, Vol. 75, No. 26, 2006, Article ID: 124701. http://dx.doi.org/10.1143/JPSJ.75.124701 [2] M. Lazzeri and F. Mauri, “Nonadiabatic Kohn Anomaly in a Doped Graphene Monolayer,” Physical Review Letters, Vol. 97, No. 12, 2006, Article ID: 266407.
http://dx.doi.org/10.1103/PhysRevLett.97.266407 [3] S. Pisana, M. Lazzeri, C. Casiraghi, K. S. Novoselov, A. K. Geim, A. C. Ferrari and F. Mauri, “Breakdown of the Adiabatic Born-Oppenheimer Approximation in Graphene,” Nature Materials, Vol. 6, No. 3, 2007, pp. 198-201. http://dx.doi.org/10.1038/nmat1846 [4] J. Yan, Y. Zhang, P. Kim and A. Pinczuk, “Electric Field Effect Tuning of Electron-Phonon Coupling in Graphene,” Physical Review Letters, Vol. 98, No. 16, 2007, Article ID: 166802. http://dx.doi.org/10.1103/PhysRevLett.98.166802 [5] A. Das, S. Pisana, B. Chakraborty, S. Piscanec, S. K. Saha, U. V. Waghmare, K. S. Novoselov, H. R. Krish- namurthy, A. K. Geim, A. C. Ferrari and A. K. Sood, “Monitoring Dopants by Raman Scattering in an Electro- chemically Top-Gated Graphene Transistor,” Nature Nanotechnology, Vol. 3, No. 4, 2008, pp. 210-2015. http://dx.doi.org/10.1038/nnano.2008.67 [6] T. Ando, “Anomaly of Optical Phonons in Bilayer Graphene,” Journal of the Physical Society of Japan, Vol. 76, No. 10, 2007, Article ID: 104711. http://dx.doi.org/10.1143/JPSJ.76.104711 [7] J. Yan, E. A. Henriksen, P. Kim and A. Pinczuk, “Observation of Anomalous Phonon Softening in Bilayer Graphene,” Physical Review Letters, Vol. 101, No. 13, 2008, Article ID: 136804. http://dx.doi.org/10.1103/PhysRevLett.101.136804 [8] L. M. Malard, D. C. Elias, E. S. Alves and M. A. Pimenta, “Observation of Distinct Electron-Phonon Couplings in Gated Bilayer Graphene,” Physical Review Letters, Vol. 101, No. 25, 2008, Article ID: 257401. http://dx.doi.org/10.1103/PhysRevLett.101.257401 [9] J. Yan, T. Villarson, E. A. Henriksen, P. Kim and A. Pinczuk, “Optical Phonon Mixing in Bilayer Graphene with a Broken Inversion Symmetry,” Physical Review B, Vol. 80, No. 24, 2008, Article ID: 241417. http://dx.doi.org/10.1103/PhysRevB.80.241417 [10] T. Ta Tang, Y. Zhang, Ch.-H. Park, B. Geng, C. Girit, Z. Hao, M. C. Martin, A. Zettl, M. F. Crommie, S. G. Louie, Y. R. Shen and F. Wang, “A Tunable Phonon-Exciton Fano System in Bilayer Graphene,” Nature Nanotechnology, Vol. 5, 2010, pp. 32-36. [11] A. B. Kuzmenko, L. Benfatto, E. Cappelluti, I. Crassee, D. van der Marel, P. Blake, K. S. Novoselov and A. K. Geim, “Gate Tunable Infrared Phonon Anomalies in Bilayer Graphene,” Physical Review Letters, Vol. 103, No. 11, 2009, Article ID: 116804. http://dx.doi.org/10.1103/PhysRevLett.103.116804 [12] U. Fano, “Effects of Configuration Interaction on Intensities and Phase Shifts,” Physical Review, Vol. 124, No. 6, 1961, pp. 1866-1878. http://dx.doi.org/10.1103/PhysRev.124.1866 [13] P. C. Eklund and K. R. Subbaswamy, “Analysis of Breit- Wigner Line Shapes in the Raman Spectra of Graphite Intercalation Compounds,” Physical Review B, Vol. 20, No. 12, 1979, pp. 5157-5161. http://dx.doi.org/10.1103/PhysRevB.20.5157 [14] Z. H. Wang, M. S. Dresselhaus, G. Dresselhaus and P. C. Eklund, “Raman Studies of Electron-Phonon Interaction in KxC70,” Physical Review B, Vol. 48, No. 22, 1993, pp. 16881-16884. http://dx.doi.org/10.1103/PhysRevB.48.16881 [15] S. D. M. Brown, A. Jorio, P. Corio, M. S. Dresselhaus, G. Dresselhaus, R. Saito and K. Kneipp, “Origin of the Breit-Wigner-Fano Lineshape of the Tangential G-Band Feature of Metallic Carbon nanotubes,” Physical Review B, Vol. 63, No. 15, 2001, Article ID: 155414.
http://dx.doi.org/10.1103/PhysRevB.63.155414 [16] M. Manzardo, E. Cappelluti, E. van Heumen and A. B. Kuzmenko, “A Crucial Role in This Context Is Played by the Particle-Hole Asymmetry of the Electronic π-Bands,” Physical Review B, 2012. http://arxiv.org/abs/1205.4907 [17] Z. Li, Ch. H. Lui, E. Cappelluti, L. Benfatto, K. Mak, G. L. Carr, J. Shan and T. F. Heinz, “Structure-Dependent Fano Resonances in the Infrared Spectra of Phonons in Few-Layer Graphene,” Physical Review Letters, Vol. 108, No. 15, 2012, Article ID: 156801.
http://dx.doi.org/10.1103/PhysRevLett.108.156801 [18] W. Strupinski, K. Grodecki, A. Wysmolek, R. Stepniewski, T. Szkopek, P. E. Gaskell, A. Grüneis, D. Haberer, R. Bozek, J. Krupka and J. M. Baranowski, “Graphene Epitaxy by Chemical Vapor Deposition on SiC,” Nano Letters, Vol. 11, No. 4, 2011, pp. 1786-1791. http://dx.doi.org/10.1021/nl200390e [19] K. V. Emtsev, F. Speck, T. Seyller, L. Ley and J. D. Riley, “Interaction, Growth, and Ordering of Epitaxial Graphene on SiC{0001} Surfaces: A Comparative Photoelectron Spectroscopy Study,” Physical Review B, Vol. 77, No. 15, 2008, Article ID: 155303.
http://dx.doi.org/10.1103/PhysRevB.77.155303 [20] C. Riedl, C. Coletti, T. Iwasaki, A. A. Zakharov and U. Starke, “Quasi-Free-Standing Epitaxial Graphene on SiC Obtained by Hydrogen Intercalation,” Physical Review Letters, Vol. 103, No. 24, 2009, Article ID: 246804. http://dx.doi.org/10.1103/PhysRevLett.103.246804 [21] C. Virojanadara, A. A. Zakharov, R. Yakimova, L. I. Johansson, “Buffer Layer Free Large Area Bi-Layer Graphene on SiC(0 0 0 1),” Surface Science, Vol. 604, No. 2, 2010, pp. L4-L7.
http://dx.doi.org/10.1016/j.susc.2009.11.011 [22] F. Speck, J. Jobst, F. Fromm, M. Ostler, D. Waldmann, M. Hundhausen, H. B. Weber and Th. Seyller, “The Quasi- Free-Standing Nature of Graphene on H-Saturated SiC (0001),” Physical Review Letters, Vol. 99, No. 12, 2011, Article ID: 122106. http://dx.doi.org/10.1063/1.3643034 [23] Z. Li, Ch. H. Lui, E. Cappelluti, L. Benfatto, K. F. Mak, G. L. Carr, J. Shan and T. F. Heinz, “Structure-Dependent Fano Resonances in the Infrared Spectra of Phonons in Few-Layer Graphene,” Physical Review Letters, Vol. 108, No. 15, 2012, Article ID: 156801.
http://dx.doi.org/10.1103/PhysRevLett.108.156801 [24] M. J. Rice and H.-Y. Choi, “Charged-Phonon Absorption in Doped C60,” Physical Review B, Vol. 45, No. 17, 1992, pp. 10173-10176. http://dx.doi.org/10.1103/PhysRevB.45.10173 [25] M. J. Rice, “Organic Linear Conductors as Systems for the Study of Electron-Phonon Interactions in the Organic Solid State,” Physical Review Letters, Vol. 37, No. 1, 1976, pp. 36-39. http://dx.doi.org/10.1103/PhysRevLett.37.36 [26] E. Cappelluti, L. Benfatto and A. B. Kuzmenko, “Phonon Switching and Combined Fano-Rice Effect in Optical Spectra of Bilayer Graphene,” Physical Review B, Vol. 82, No. 4, 2010, Article ID: 041402. http://dx.doi.org/10.1103/PhysRevB.82.041402