Enhanced Thermoelectric Power in Graphene: Violation of the Mott Relation by Inelastic Scattering

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Enhanced Thermoelectric Power in Graphene: Violation of the Mott Relation by Inelastic Scattering

Fereshte Ghahari, Hong-Yi Xie, Takashi Taniguchi, Kenji Watanabe, Matthew S. Foster, and Philip Kim

Phys. Rev. Lett. 116, 136802 – Published 29 March 2016

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.

Received 24 January 2016

DOI:https://doi.org/10.1103/PhysRevLett.116.136802

Physics Subject Headings (PhySH)

Phonons Thermoelectric effects

Graphene Mott insulators

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Fereshte Ghahari¹, Hong-Yi Xie², Takashi Taniguchi³, Kenji Watanabe³, Matthew S. Foster^2,4, and Philip Kim^1,5

¹Department of Physics, Columbia University, New York, New York 10027, USA
²Physics and Astronomy Department, Rice University, Houston, Texas 77005, USA
³National Institute for Material Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
⁴Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
⁵Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA