Raman spectroscopy study of rotated double-layer graphene: Misorientation-angle dependence of electronic structure

TL;DR

This study systematically investigates how the electronic structure of rotated double-layer graphene affects its Raman spectra, revealing angle-dependent spectral features and providing a method to determine rotation angles.

Contribution

It offers a combined experimental and theoretical analysis of the angle-dependent Raman spectra of rotated double-layer graphene, enhancing understanding of its electronic band structure.

Findings

Raman spectra vary significantly with rotation angle.

Theoretical analysis links spectral features to electronic band structure changes.

Provides a practical method to identify rotation angles in double-layer graphene.

Abstract

We present a systematic Raman study of unconventionally-stacked double-layer graphene, and find that the spectrum strongly depends on the relative rotation angle between layers. Rotation-dependent trends in the position, width and intensity of graphene 2D and G peaks are experimentally established and accounted for theoretically. Our theoretical analysis reveals that changes in electronic band structure due to the interlayer interaction, such as rotational-angle dependent Van Hove singularities, are responsible for the observed spectra features. Our combined experimental and theoretical study provides a deeper understanding of the electronic band structure of rotated double-layer graphene, and leads to a practical way to identify and analyze rotation angles of misoriented double-layer graphene.