Berlin 2012 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 22: Graphene: Structure and Theory II

HL 22.5: Talk

Monday, March 26, 2012, 18:15–18:30, EW 201

Electron Scattering by Buffer Layer Acoustic Phonons in Graphene on SiC Si-face — •Nicolas Ray, Sam Shallcross, and Oleg Pankratov — Theoretische Festkörperphysik, Universität Erlangen, Staudtstr. 7B2, 91058 Erlangen

Graphene grown epitaxially on SiC presents one of the most promising routes towards the technological implementation of graphene, as well as being an interesting physical system in its own right. Key features of this system are a doping which places the Fermi level ≈ 450 meV above the Dirac point, and a much reduced electron mobility (≈ 3000 cm²/V.s at room temperature). In this work we describe a mechanism in which accoustic surface phonons modify the graphene-substrate separation resulting in a deformation potential and hence electron scattering. With this model we then calculate transport properties within the Boltzmann formalism, finding agreement with recent experimental work [1] demonstrating a remarkable decrease in the resistivity (ρ) near the Dirac with increasing temperature (T), a linear increase of ρ with T away from the Dirac point, and a good description of the graphene electron mobility.

[1] S. Tanabe et al. Phys. Rev. B 84, 115458 (2011)