Emergence of Topological Electron Crystals in Bilayer Graphene--Mott Insulator Heterostructures

TL;DR

This paper predicts the formation of topological electron crystals in bilayer graphene--Mott insulator heterostructures driven by Coulomb interactions and miniband physics, revealing new crystalline orders with potential topological properties.

Contribution

It introduces a theoretical framework showing how interlayer Coulomb attraction and miniband effects stabilize novel topological electron crystal phases in bilayer heterostructures.

Findings

Stable electron crystals with triangular, honeycomb, and kagome geometries are predicted.

Charge distribution is reshaped by bilayer wave functions, favoring nontrivial crystalline orders.

Distinct Hall responses are associated with different topological electron crystal phases.

Abstract

We predict topological electron crystals driven by the interplay of interlayer Coulomb attraction and topological miniband physics in bilayer graphene--Mott insulator heterostructures. Charge transfer creates a charge neutral, mass asymmetric electron hole bilayer, in which itinerant carriers in bilayer graphene interact attractively with heavy, localized carriers in a flat Hubbard band. In the dilute and heavy fermion limits, this competition overturns the conventional preference for triangular Wigner ordering and stabilizes electron crystals with triangular, honeycomb, and kagome geometries. Using self-consistent Hartree Fock calculations, we show that the nonlocal structure of the bilayer graphene wave functions reshapes the charge distribution and favors nontrivial crystalline orders at moderate interlayer attraction. These phases host distinct Hall responses, establishing a route to engineering topological electron crystals without moir\'e twisting or externally patterned superlattices.