  We discuss the conditions under which the predicted (but not yet observed)
zero-field interlayer excitonic condensation in double layer graphene has a
critical temperature high enough to allow detection. Crucially, disorder
arising from charged impurities and corrugation in the lattice structure ---
invariably present in all real samples --- affects the formation of the
condensate via the induced charge inhomogeneity. In the former case, we use a
numerical Thomas-Fermi-Dirac theory to describe the local fluctuations in the
electronic density in double layer graphene devices and estimate the effect
these realistic fluctuations have on the formation of the condensate. To make
this estimate, we calculate the critical temperature for the interlayer
excitonic superfluid transition within the mean-field BCS theory for both
optimistic (unscreened) and conservative (statically screened) approximations
for the screening of the interlayer Coulomb interaction. We also estimate the
effect of allowing dynamic contributions to the interlayer screening. We then
conduct similar calculations for double quadratic bilayer graphene, showing
that the quadratic nature of the low-energy bands produces pairing with
critical temperature of the same order of magnitude as the linear bands of
double monolayer graphene.
