Exploring interlayer Dirac cone coupling in commensurately rotated few-layer graphene on SiC(000-1)

TL;DR

This study examines how the electronic band structure of few-layer graphene on SiC(000-1) is affected by interlayer rotation, revealing Dirac cone diffraction and superlattice effects through reciprocal space imaging.

Contribution

It provides new insights into the interlayer Dirac cone coupling and superlattice formation in rotated few-layer graphene on SiC(000-1).

Findings

Identification of Dirac cone diffraction patterns.

Observation of superlattice-induced Dirac cone replicas.

Correlation between rotation angles and superlattice structures.

Abstract

We investigate electronic band-structure images in reciprocal space of few layer graphene epitaxially grown on SiC(000-1). In addition to the observation of commensurate rotation angles of the graphene layers, the k-space images recorded near the Fermi edge highlight structures originating from diffraction of the Dirac cones due to the relative rotation of adjacent layers. The 21.9{\deg} and 27{\deg} rotation angles between two sheets of graphene are responsible for a periodic pattern that can be described with a superlattice unit cells. The superlattice generates replicas of Dirac cones with smaller wave vectors, due to a Brillouin zone folding.