Regensburg 2010 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 26: Spin-controlled Transport II

HL 26.2: Talk

Tuesday, March 23, 2010, 14:15–14:30, H14

Tight binding model of spin-orbit coupling in graphene — •Sergej Konschuh, Martin Gmitra, and Jaroslav Fabian — Universität Regensburg, Regensburg, Germany

We construct a tight-binding model to explain the spin-orbit coupling effects on the electronic band structure of graphene. We expand the wave functions into a combination of the atomic (s,p,d)-orbitals. We show that the usually neglected d-orbital states contribute to the spin-orbit splitting at the K(K') points in the first order; the s and p orbitals contribute in the second order, qualitatively explaining our recent first-principles results. In contrast, the d-orbitals play no role in the so called extrinsic SOC effect, which is the spin-orbit splitting in the presence of a transverse (to the plane) electric field. Analytical results are derived for the spin-orbit splitting in terms of the atomic energies, hopping and overlap integrals, as well as the atomic spin-orbit splittings.

This work is supported by the DFG SPP1285.