Mesoscopic conductance fluctuations in graphene samples
Abstract
Mesoscopic conductance fluctuations in graphene samples at energies not very close to the Dirac point are studied analytically. We demonstrate that the conductance variance <[δ G]2> 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 <[δ G]2 > = 4 < [δ G]2 >metal is four times greater than that in conventional metals, which is due to the two-fold valley degeneracy. In the absence of intervalley scattering, but for strong intravalley scattering and/or strong warping <[δ G]2 > =2 < [δ G]2 >metal. Only in the limit of strong intervalley scattering <[δ G]2 > = < [δ G]2 >metal. Our theory explains recent numerical results and can be used for comparison with existing experiments.