(40c) Thermal and Thermoelectric Transport Coefficients in Graphene

in graphene

Enrique Muñoz, Physics Institute, Pontificia Universidad Católica de Chile, Vicuña Mackenna 4860, Santiago, Chile.

Abstract

Thermal, electronic and thermoelectric transport coefficients in graphene were studied. The effect of electron-phonon scattering processes, as well as the presence of C¹³ isotopes over the thermoelectric properties of extrinsic graphene were considered. Electron-phonon interaction is described within the deformation potential approximation. Electrical and thermal resistivity, as well as the thermopower, were calculated within the Bloch theory approximations. Analytical expressions for the different transport coefficients were obtained from a variational solution of the Boltzmann transport equation. The phonon-limited electrical resistivity ρeâ??ph shows a linear in temperature dependence at high temperatures, and follows a ρeâ??ph â?¼ T⁴at low temperatures, in agreement with experiments. The phonon-limited thermal resistivity at low temperatures exhibits aâ?¼Tdependence and achieves a nearly constant value at high temperatures. The predicted Seebeck coefficient at very low temperature isQ(T)â?¼Ï?²kB T/(3eEF), which shows a n^â??1/2 dependence with the carrier density n, in agreement with experiments. On the other hand, the presence of a random distribution of C¹³ isotopes at fixed concentrations was studied as an strategy to reduce the lattice thermal conductivity, with the corresponding enhancement of the figure of merit for thermoelectric applications.[3]

[1] E. Muñoz, Journal of Physics: Condensed Matter 24 (2012), 195302.

[2] E. Muñoz, J. Lu and B. I. Yakobson, Nano Letters 10 (2010), 1652.

[3] E. Muñoz, submitted (2016).