Tunable moiré bands and strong correlations in small-twist-angle bilayer graphene

According to electronic structure theory, bilayer graphene is expected to have anomalous electronic properties when it has long-period moiré patterns produced by small misalignments between its individual layer honeycomb lattices. We have realized bilayer graphene moiré crystals with accurately controlled twist angles smaller than 1° and studied their properties using scanning probe microscopy and electron transport. We observe conductivity minima at charge neutrality, satellite gaps that appear at anomalous carrier densities for twist angles smaller than 1°, and tunneling densities-of-states that are strongly dependent on carrier density. These features are robust up to large transverse electric fields. In…

• NS
  National Science Foundation

  Awards: EECS-1610008, DMR-1157490, EECS-1607911
• SR
  Semiconductor Research Corporation
• S
  Samsung
• AR
  Army Research Office

  Award: W911NF-14-1-0653