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Weak localisation magnetoresistance and valley symmetry in graphene

E. McCann·K. Kechedzhi·Vladimir I. Fal'ko·H. Suzuura·T. Ando·B. L. Altshuler
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Abstract

Due to the chiral nature of electrons in a monolayer of graphite (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 conventional negative magnetoresistance. We show this by evaluating the dependence of the magnetoresistance of graphene on relaxation rates associated with various possible ways of breaking a 'hidden' valley symmetry of the system.

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E. McCann, K. Kechedzhi, Vladimir I. Fal'ko, H. Suzuura, T. Ando, B. L. Altshuler. 2006-10-17. Weak localisation magnetoresistance and valley symmetry in graphene. https://doi.org/10.1103/physrevlett.97.146805

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