title: Enhanced Thermoelectric Power in Graphene: Violation of the Mott Relation by Inelastic Scattering.
abstract: We report the enhancement of the thermoelectric power (TEP) in graphene with extremely low disorder. At high temperature we observe that the TEP is substantially larger than the prediction of the Mott relation, approaching to the hydrodynamic limit due to strong inelastic scattering among the charge carriers. However, closer to room temperature the inelastic carrier-optical-phonon scattering becomes more significant and limits the TEP below the hydrodynamic prediction. We support our observation by employing a Boltzmann theory incorporating disorder, electron interactions, and optical phonons.
authors.affiliation: Department of Physics, Columbia University, New York, New York 10027, USA.
authors.forename: Fereshte
authors.initials: F
authors.lastname: Ghahari
authors.affiliation: Physics and Astronomy Department, Rice University, Houston, Texas 77005, USA.
authors.forename: Hong-Yi
authors.initials: HY
authors.lastname: Xie
authors.affiliation: National Institute for Material Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Taniguchi
authors.affiliation: National Institute for Material Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Watanabe
authors.affiliation: Physics and Astronomy Department, Rice University, Houston, Texas 77005, USA.|Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA.
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Foster
authors.affiliation: Department of Physics, Columbia University, New York, New York 10027, USA.|Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.
authors.forename: Philip
authors.initials: P
authors.lastname: Kim