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arXiv · 1201.4661

Unraveling the acoustic electron-phonon interaction in graphene

Kristen Kaasbjerg·Kristian S. Thygesen·Karsten W. Jacobsen
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Abstract

Using a first-principles approach we calculate the acoustic electron-phonon couplings in graphene for the transverse (TA) and longitudinal (LA) acoustic phonons. Analytic forms of the coupling matrix elements valid in the long-wavelength limit are found to give an almost quantitative description of the first-principles based matrix elements even at shorter wavelengths. Using the analytic forms of the coupling matrix elements, we study the acoustic phonon-limited carrier mobility for temperatures 0-200 K and high carrier densities of 10^{12}-10^{13} cm^{-2}. We find that the intrinsic effective acoustic deformation potential of graphene is \Xi_eff = 6.8 eV and that the temperature dependence of the mobility \mu ~ T^{-\alpha} increases beyond an \alpha = 4 dependence even in the absence of screening when the full coupling matrix elements are considered. The large disagreement between our calculated deformation potential and those extracted from experimental measurements (18-29 eV) indicates that additional or modified acoustic phonon-scattering mechanisms are at play in experimental situations.

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Kristen Kaasbjerg, Kristian S. Thygesen, Karsten W. Jacobsen. 2012-01-23. Unraveling the acoustic electron-phonon interaction in graphene. https://doi.org/10.1103/physrevb.85.165440

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