Universal conductance fluctuations in graphene

Maxim Kharitonov

Theoretical Physics III, Ruhr University, Germany

Universal conductance fluctuations (UCF) in graphene samples at energies not very close to the Dirac point are studied analytically. We demonstrate that the conductance variance is very sensitive to the elastic scattering breaking the valley symmetry. In the absence of such scattering (disorder potential smooth at atomic scales, trigonal warping negligible), the variance is 4 times greater than that in conventional metals, which explains a recent unexpected numerical finding. Strong intravalley scattering and/or warping reduce this factor to 2 and only the intervalley scattering leads to same result as for conventional metals. Different universal values of the variance, when compared with experimental data, can provide important information about disorder in the system.