  In this work, we study a molecular graphene model on the top of a
superconductor in the presence of pseudomagnetic fields induced by coplanar
strain fields. With the pseudomagnetic fields and the attractive interaction
induced from the substrate, a flat band superconductor can be achieved
according to mean field analysis on the effective Hamiltonian. Based on a
semiclassical approximation, we first show that the orbital limit is hugely
enhanced by the pseudomagnetic fields. The physical reason is that the orbital
angular momenta locking at $K$ and $K'$ valleys due to the pseudomagnetic
fields suppress the orbital magnetization from external magnetic fields.
Considering the vanishing band width in this system, we then study the effects
of Gaussian fluctuations in both Hartree and pairing channels. We show that in
the dilute limit, the phase transition is dominated by collective modes with
critical temperatures much lower than the mean field results. At half filling,
our method gives no corrections to the mean field critical temperatures.
