학술논문
Probing enhanced electron-phonon coupling in graphene by infrared resonance Raman spectroscopy
Document Type
Working Paper
Author
Venanzi, Tommaso; Graziotto, Lorenzo; Macheda, Francesco; Sotgiu, Simone; Ouaj, Taoufiq; Stellino, Elena; Fasolato, Claudia; Postorino, Paolo; Mišeikis, Vaidotas; Metzelaars, Marvin; Kögerler, Paul; Beschoten, Bernd; Coletti, Camilla; Roddaro, Stefano; Calandra, Matteo; Ortolani, Michele; Stampfer, Christoph; Mauri, Francesco; Baldassarre, Leonetta
Source
Subject
Language
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 $\mathbf{K}$, we unveil a giant increase of the intensity ratio between the double-resonant 2D and 2D$^\prime$ peaks with respect to that measured in graphite. Comparing with fully \textit{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.
Comment: 6 pages, 3 figures
Comment: 6 pages, 3 figures