Fingerprints of stacking order in graphene layers from ab initio second-order Raman spectra

TL;DR

This study uses ab initio density-functional theory to analyze how stacking arrangements in graphene layers influence first- and second-order Raman spectra, providing a tool for identifying structural signatures.

Contribution

It offers a systematic ab initio analysis of Raman spectra across various graphene stacking configurations, highlighting spectral signatures specific to each structure.

Findings

First-order G-band is similar across structures

Second-order 2D-band shows structure-specific signatures

Spectral analysis can identify stacking arrangements

Abstract

We present an \textit{ab initio} study based on density-functional theory of first- and second-order Raman spectra of graphene-based materials with different stacking arrangements and numbers of layers. Going from monolayer and bilayer graphene to periodic graphitic structures, we investigate the behavior of the first-order G-band and of the second-order 2D-band excited by the same set of photon energies. The former turns out to be very similar in all considered graphene-based materials, while in the latter we find the signatures of individual structures. With a systematic analysis of the second-order Raman spectra at varying frenquency of the incident radiation, we monitor the Raman signal and identify the contributions from different phonon modes that are characteristic of each specific arrangement. Supported by good agreement with experimental findings and with previous theoretical studies based on alternative approaches, our results propose an effective tool to probe and analyze the fingerprints of graphene-based and other low-dimensional materials.