Interlayer repulsion and decoupling effects in stacked turbostratic graphene flakes

TL;DR

This paper investigates how interlayer repulsion influences electronic properties and decoupling in stacked turbostratic graphene flakes, revealing that layer misorientation and lattice distortions help mitigate repulsive interactions.

Contribution

It provides a quantum chemistry analysis of interlayer repulsion effects and explains the decoupling phenomena in misoriented graphene layers.

Findings

Repulsive interactions dominate in AA stacking, causing decoupling.

Layer misorientation reduces interlayer repulsion and stabilizes the system.

Moiré pattern regions exhibit lattice distortions due to interlayer repulsion.

Abstract

We have explored the electronic properties of stacked graphene flakes with the help of the quantum chemistry methods. We found that the behavior of a bilayer system is governed by the strength of the repulsive interactions that arise between the layers as a result of the orthogonality of their $\pi$ orbitals. The decoupling effect, seen experimentally in AA stacked layers is a result of the repulsion being dominant over the orbital interactions and the observed layer misorientation of 2$^{\circ}-5^{\circ}$ is an attempt by the system to suppress that repulsion and stabilize itself. For misorientated graphene, in the regions of superposed lattices in the Moir\'e pattern, the repulsion between the layers induce lattice distortion in the form of a bump or, in rigid systems local interlayer decoupling.