Composite super-moir\'e lattices in double aligned graphene heterostructures

TL;DR

This paper introduces a method using double aligned graphene with two hexagonal boron nitride layers to enable electronic spectrum reconstruction at all energies through differential moiré patterns, overcoming previous energy range limitations.

Contribution

The study demonstrates a novel approach to spectrum reconstruction at all energies by leveraging differential moiré patterns in double aligned graphene heterostructures.

Findings

Spectrum reconstruction at arbitrarily low energies achieved.

Strength of potential depends on atomic reconstruction within the super-cell.

Tunable electronic spectra in 2D materials demonstrated.

Abstract

When two-dimensional atomic crystals are brought into close proximity to form a van der Waals heterostructure, neighbouring crystals can start influencing each others electronic properties. Of particular interest is the situation when the periodicity of the two crystals closely match and a moir\'e pattern forms, which results in specific electron scattering, reconstruction of electronic and excitonic spectra, crystal reconstruction, and many other effects. Thus, formation of moir\'e patterns is a viable tool of controlling the electronic properties of 2D materials. At the same time, the difference in the interatomic distances for the two crystals combined, determines the range in which the electronic spectrum is reconstructed, and thus is a barrier to the low energy regime. Here we present a way which allows spectrum reconstruction at all energies. By using graphene which is aligned simultaneously to two hexagonal boron nitride layers, one can make electrons scatter in the differential moir\'e pattern, which can have arbitrarily small wavevector and, thus results in spectrum reconstruction at arbitrarily low energies. We demonstrate that the strength of such a potential relies crucially on the atomic reconstruction of graphene within the differential moir\'e super-cell. Such structures offer further opportunity in tuning the electronic spectra of two-dimensional materials.