  Minimally twisted bilayer graphene in the presence of an interlayer bias
develops a triangular network of valley chiral modes that propagate along the
$AB/BA$ interfaces and scatter at the $AA$ regions. The low energy physics of
the resulting network can be captured by means of a phenomenological scattering
network model, allowing to calculate the energy spectrum and the
magnetoconductance in a straightforward way. Although there is in general a
good agreement between microscopic and phenomenological models, there are some
aspects that have not been captured so far with the latter. In particular, the
appearance of flatbands in the energy spectrum associated to a localized
density of states at the $AA$ regions. To bring both approaches closer
together, we modify the previous energy independent phenomenological model and
add the possibility to scatter to a set of discrete energy levels at the $AA$
regions, yielding a $S$ matrix with energy dependent parameters. Furthermore,
we investigate the impact of Coulomb repulsion in these regions on a mean-field
level and discuss possible effects of decoherence due to elastic and inelastic
cotunneling events.
