We report on resonance Raman spectroscopy measurements with excitation photon energy down to 1.16 eV on graphene, to study how low-energy carriers interact with lattice vibrations. Thanks to the excitation energy close to the Dirac point at K, we unveil a giant increase of the intensity ratio between the double-resonant 2D and 2D' peaks with respect to that measured in graphite. Comparing with fully ab initio theoretical calculations, we conclude that the observation is explained by an enhanced, momentum -dependent coupling between electrons and Brillouin zone-boundary optical phonons. This finding applies to two-dimensional Dirac systems and has important consequences for the modeling of transport in graphene devices operating at room temperature.
Probing Enhanced Electron-Phonon Coupling in Graphene by Infrared Resonance Raman Spectroscopy / Venanzi, T.; Graziotto, L.; Macheda, F.; Sotgiu, S.; Ouaj, T.; Stellino, E.; Fasolato, C.; Postorino, P.; Miseikis, V.; Metzelaars, M.; Kogerler, P.; Beschoten, B.; Coletti, C.; Roddaro, S.; Calandra, M.; Ortolani, M.; Stampfer, C.; Mauri, F.; Baldassarre, L.. - In: PHYSICAL REVIEW LETTERS. - ISSN 1079-7114. - 130:25(2023), p. 256901. [10.1103/PhysRevLett.130.256901]
Probing Enhanced Electron-Phonon Coupling in Graphene by Infrared Resonance Raman Spectroscopy
Venanzi T.;Macheda F.;Sotgiu S.;Stellino E.;Fasolato C.;Postorino P.;Ortolani M.;Mauri F.;Baldassarre L.
2023
Abstract
We report on resonance Raman spectroscopy measurements with excitation photon energy down to 1.16 eV on graphene, to study how low-energy carriers interact with lattice vibrations. Thanks to the excitation energy close to the Dirac point at K, we unveil a giant increase of the intensity ratio between the double-resonant 2D and 2D' peaks with respect to that measured in graphite. Comparing with fully ab initio theoretical calculations, we conclude that the observation is explained by an enhanced, momentum -dependent coupling between electrons and Brillouin zone-boundary optical phonons. This finding applies to two-dimensional Dirac systems and has important consequences for the modeling of transport in graphene devices operating at room temperature.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
