Quantum interference corrections to magnetoconductivity in graphene

We studied weak localization (WL) and antilocalization (WAL) in graphene at temperatures between 0.3 K and 15 K. At low carrier density, we observed a transition fromWL toWAL driven by the increasing of the magnetic field while at high carrier density, WAL was suppressed as a consequence of trigonal warping of the conical energy bands.We analyzed the magnetic-field-driven WL-WAL transition, evaluating the relative strengths of the various elastic-scattering mechanisms and estimating the decoherence lengths and rates as a function of temperature, using an alternative method with respect to previously reported studies. We relate the small values of lφ here reported, confirmed by a complementary analysis of universal conductance fluctuations, to an effective breaking of time-reversal symmetry due to the slowly varying disorder of the long-range type.