Dacen Waters

In certain materials, electrons confined to two dimensions can exhibit unusual quantum behaviors, giving rise to exotic phases of matter. Moiré materials—formed when two crystal layers are slightly misaligned—create unique electronic environments where interactions between electrons become dominant. These interactions can lead to topological states, including quantum Hall-like effects that occur without an external magnetic field.

Abstract In a dilute two-dimensional electron gas, Coulomb interactions can stabilize the formation of a Wigner crystal1,2,3. Although Wigner crystals are topologically trivial, it has been predicted that electrons in a partially filled band can break continuous translational symmetry and time-reversal symmetry spontaneously, resulting in a type of topological electron crystal known as an anomalous Hall crystal4,5,6,7,8,9,10,11.

Abstract Moiré materials host a wealth of intertwined correlated and topological states of matter, all arising from flat electronic bands with nontrivial quantum geometry. A prominent example is the family of alternating-twist magic-angle graphene stacks, which exhibit symmetry-broken states at rational fillings of the moiré band and superconductivity close to half filling.