  We derive a minimal low-energy model for Bernal bilayer graphene and related
rhombohedral graphene multilayers at low electronic densities by constructing
Wannier orbitals defined in real-space supercells of the original primitive
cell. Starting from an ab-initio electronic structure theory comprising the
atomic carbon $p_z$-orbitals, momentum locality of the Fermi surface pockets
around $K,K'$ is circumvented by backfolding the $\pi$-bands to the concomitant
mini-Brillouin zone of the supercell, reminiscent of their (twisted) moir\'e
counterparts. The supercell Wannier functions reproduce the spectral weight and
Berry curvature of the microscopic model and offer an intuitive real-space
picture of the emergent physics at low electronic densities being shaped by
flavor-polarized wave packets with mesoscopic extent. By projecting an
orbital-resolved, dual-gated Coulomb interaction to the effective Wannier
basis, we find that the low-energy physics of Bernal bilayer graphene is
governed by weak electron-electron interactions. Our study bridges between
existing continuum theories and ab-initio studies of small Fermi pocket systems
like rhombohedral graphene stacks by providing a symmetric lattice description
of their low-energy physics.
