Photoelectron diffraction of twisted bilayer graphene

TL;DR

This paper evaluates the effectiveness of photoelectron diffraction (PED) in determining the atomic structure of twisted bilayer graphene, including stacking and twist angles, through theoretical analysis and calculations.

Contribution

It provides a comprehensive theoretical assessment of PED's capability to characterize structural properties of twisted bilayer graphene, a novel application for this technique.

Findings

PED can distinguish different stacking configurations in bilayer graphene.

PED is sensitive to twist angles and interlayer distances.

Theoretical models match experimental expectations for vdW heterostructures.

Abstract

Photoelectron diffraction (PED) is a powerful spectroscopic technique that combines elemental resolution with a high sensitivity to the local atomic arrangement at crystal surfaces, thus providing unique fingerprints of selected atomic sites in matter. Stimulated by the rapid innovation in the development of various analysis methods for probing the atomic and electronic structures of van der Waals (vdW) heterostructures of two-dimensional materials, we present a theoretical assessment of the capacity of PED for extracting structural properties such as stacking, twist angles and interlayer distances. We provide a complete description of PED for the benchmark vdW heterostructure bilayer graphene (BLG), by calculating and analyzing the PED of BLG in Bernal and AA-stacking as well as twisted BLG for a wide range of the twist angle.