Weak localisation and spin-orbit coupling in graphene

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• Dr Edward McCann, U of Lancaster
• Thursday 14 January 2010, 13:45-15:00
• Theory Library.

If you have a question about this talk, please contact Dr Dimitri M Gangardt.

In the first part of this talk, I’ll review the tight-binding model of the electronic properties of graphene. Then, I’ll discuss the theory of weak localisation in graphene. Due to the chiral nature of electrons in graphene, one can expect weak antilocalisation and a positive weak-field magnetoresistance in it. However, trigonal warping (which breaks p/?p symmetry of the Fermi line in each valley) suppresses antilocalisation, while inter-valley scattering due to atomically sharp scatterers in a realistic graphene sheet or by edges in a narrow wire tends to restore the conventional weak localisation effect.

So far, the story of weak localisation in graphene has involved the interplay of additional spinlike quantum numbers, related to lattice and valley degrees of freedom, but not the electronic spin itself. Spin-orbit coupling may be an alternative way to induce weak antilocalisation in graphene, as in conventional conductors, but its observation is likely to be challenging in view of the predicted weakness of the spin-orbit interaction in graphene. In the second part of the talk, I’ll explain how the theory of weak localisation in graphene may be modified to take into account the influence of spin-orbit coupling.

This talk is part of the Theoretical Physics Seminars series.

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• Bham Talks
• Theoretical Physics Seminars
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