  Bernal bilayer graphene has recently been discovered to exhibit a wide range
of unique ordered phases resulting from interaction-driven effects and
encompassing spin and valley magnetism, correlated insulators, correlated
metals, and superconductivity. This letter reports on a novel family of
correlated phases characterized by spin and valley ordering, observed in
electron-doped bilayer graphene. The novel correlated phases demonstrate an
intriguing non-linear current-bias behavior at ultralow currents that is
sensitive to the onset of the phases and is accompanied by an insulating
temperature dependence, providing strong evidence for the presence of
unconventional charge carrying degrees of freedom originating from ordering.
These characteristics cannot be solely attributed to any of the previously
reported phases, and are qualitatively different from the behavior seen
previously on the hole-doped side. Instead, our observations align with the
presence of charge- or spin-density-waves state that open a gap on a portion of
the Fermi surface or fully gapped Wigner crystals. The resulting new phases,
quasi-insulators in which part of the Fermi surface remains intact or
valley-polarized and valley-unpolarized Wigner crystals, coexist with
previously known Stoner phases, resulting in an exceptionally intricate phase
diagram.
