Electronic Raman Scattering in Twistronic Few-Layer Graphene

TL;DR

This paper investigates electronic Raman scattering in twisted multilayer graphene, revealing two twist-angle-dependent peaks linked to moiré minibands, which can be used for non-invasive twist characterization.

Contribution

It demonstrates the presence of two distinct Raman peaks associated with moiré minibands in twistronic graphene, providing a new method for twist angle detection.

Findings

Two Raman peaks are identified, related to van Hove singularities.

Peak positions depend strongly on the twist angle.

The method enables non-invasive twist characterization.

Abstract

We study electronic contribution to the Raman scattering signals of two-, three- and four-layer graphene with layers at one of the interfaces twisted by a small angle with respect to each other. We find that the Raman spectra of these systems feature two peaks produced by van Hove singularities in moir\'{e} minibands of twistronic graphene, one related to direct hybridization of Dirac states, and the other resulting from band folding caused by moir\'{e} superlattice. The positions of both peaks strongly depend on the twist angle, so that their detection can be used for non-invasive characterization of the twist, even in hBN-encapsulated structures.