Exploring the graphene edges with coherent electron focusing

TL;DR

This paper investigates how the edge structure of graphene nanoribbons affects coherent electron focusing, revealing distinct spectral features for armchair and zigzag edges that can aid in characterisation.

Contribution

The study provides a theoretical analysis of electron focusing in graphene edges, highlighting how different edge types influence the focusing spectrum and enabling edge identification.

Findings

Armchair edges produce equidistant peaks in the focusing spectrum.

Zigzag edges show complex interference patterns at higher magnetic fields.

Edge structure influences electron focusing spectra even after structural reconstruction.

Abstract

We study theoretically the coherent electron focusing in graphene nanoribbons. Using semiclassical and numerical tight binding calculations we show that perfect armchair edges give rise to equidistant peaks in the focusing spectrum. In the case of zigzag edges at low magnetic fields one can also observe focusing peaks but with increasing magnetic field a more complex interference structure emerges in the spectrum. This difference in the spectra can be observed even if the zigzag edge undergoes structural reconstruction. Therefore transverse electron focusing can help in the identification and characterisation of the edge structure of graphene samples.