  The weak temperature dependence of the resistance R(T) of monolayer
graphene1-3 indicates an extraordinarily high intrinsic mobility of the charge
carriers. Important complications are the presence of mobile scattering centres
that strongly modify charge transport, and the presence of strong mesoscopic
conductance fluctuations that, in graphene, persist to relatively high
temperatures4,5. In this Letter, we investigate the surprisingly varied changes
in resistance that we find in graphene flakes as temperature is lowered below
70 K. We propose that these changes in R(T) arise from the temperature
dependence of the scattered electron wave interference that causes the
resistance fluctuations. Using the field effect transistor configuration, we
verify this explanation in detail from measurements of R(T) by tuning to
different gate voltages corresponding to particular features of the resistance
fluctuations. We propose simple expressions that model R(T) at both low and
high charge carrier densities.
