Orbital Quantization in a System of Edge Dirac Fermions in Nanoperforated Graphene

TL;DR

This study investigates how nanoperforation in graphene creates quantized edge states that influence electrical resistance, revealing regular peaks linked to orbitally quantized levels of Dirac fermions around nanoholes.

Contribution

It demonstrates the experimental observation of orbital quantization in edge Dirac fermions in nanoperforated graphene, confirming theoretical predictions.

Findings

Regular resistance peaks correspond to quantized edge states.

Quantization levels are consistent with Dirac fermion theory.

Nanohole-induced edge states significantly affect electronic properties.

Abstract

The dependence of the electric resistance R of nanoperforated graphene samples on the position of the Fermi level, which is varied by the gate voltage Vg, has been studied. Nanoperforation has been performed by irradiating graphene samples on a Si/SiO$_2$ substrate by heavy (xenon) or light (helium) ions. A series of regular peaks have been revealed on the R(Vg) dependence at low temperatures in zero magnetic field. These peaks are attributed to the passage of the Fermi level through an equidistant ladder of levels formed by orbitally quantized states of edge Dirac fermions rotating around each nanohole. The results are in agreement with the theory of edge states for massless Dirac fermions.