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dc.contributor.authorRemi, Sebastian Christophen_US
dc.date.accessioned2016-02-05T16:36:06Z
dc.date.available2016-02-05T16:36:06Z
dc.date.issued2014
dc.identifier.urihttps://hdl.handle.net/2144/14304
dc.description.abstractDespite the weak interaction between electrons and atomic vibrations (phonons) in the one-atom thick crystal of carbon called graphene, the scattering of electrons off phonons limits coherent electron transport in pristine devices over mesoscopic length scales. The future of graphene as a replacement to silicon and other materials in advanced electronic devices will depend on the success of controlling and optimizing electronic transport. In this dissertation, we explore the electron-phonon interaction via Raman scattering, elucidating the effects of filling and emptying charge states on the phonons in both the metallic state and when levels are quantized by an applied perpendicular magnetic field. In zero magnetic field, the phonon energy shifts due to electronic screening by charge carriers. Previously, a logarithmic divergence of the phonon energy was predicted as a function of the charge carrier density. For the first time, we observe signatures of this logarithmic divergence at liquid He temperatures after vacuum annealing on single layers. We also measure the electron-phonon coupling strength, Fermi velocity, and broadening of electronic quantum levels from Raman scattering and correlate these parameters to electronic transport. In a strong perpendicular magnetic field, the energy bands split into discrete Landau levels. Here, we observe kinks and splitting of the optical phonon energy, even when the Landau level transitions are far from resonant with the phonons. We discover that the kinks are attributed to charge filling of Landau levels, as understood from a linearized model based on electron-phonon interactions. Moreover, we show that material parameters determined without magnetic fields also describe phonon behavior in high magnetic fields.en_US
dc.language.isoen_US
dc.subjectCondensed matter physicsen_US
dc.subjectGrapheneen_US
dc.subjectRaman spectroscopyen_US
dc.titleMeasurement and control of electron-phonon interactions in grapheneen_US
dc.typeThesis/Dissertationen_US
dc.date.updated2016-01-22T18:55:38Z
etd.degree.nameDoctor of Philosophyen_US
etd.degree.leveldoctoralen_US
etd.degree.disciplinePhysicsen_US
etd.degree.grantorBoston Universityen_US


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