Tuning Superlattice Potential in Triple-Gated Bilayer Graphene

Motivated by Moiré superlattice in twisted bilayer graphene, an alternative approach of gate-defined superlattice has been used to create periodic superlattice potentials on 2d materials, with greater flexibility and tunability. Previously we have demonstrated signatures of correlated insulator phases in dual-gated Bernal-stacked bilayer graphene modulated by such gate-defined superlattice potential, manifested by a set of resistance peaks centered at carrier densities of integer multiples of single electron per unit cell of the superlattice potential. Such dual-gate device only allows access to part of the superlattice-displacement field-doping parameter space. Here we discuss our recent work on fabricating and characterizing a triple-gate device, which allows better tuning of the potential profiles, potentially allowing nontrivial band topology and its interplay with the interaction effect.