Weak localisation magnetoresistance in graphene

Edward McCann

Physics Department, Lancaster University, Lancaster, UK

The chiral nature of electrons in a monolayer of graphite (graphene) suppresses backscattering and, thus, can be expected to cause weak antilocalisation and a positive weak-field magnetoresistance. However, this can be true only for purely potential scattering, while any violation of the hexagonal symmetry by static disorder in a realistic graphene sheet or by edges in a narrow wire tend 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 the high original symmetry of the system.