Electron interference in ballistic graphene nanoconstrictions

TL;DR

This paper reports on the fabrication and observation of quantum interference phenomena in ballistic graphene nanoconstrictions, demonstrating room-temperature coherence suitable for future nanoelectronic applications.

Contribution

It introduces high-quality graphene nanoconstrictions with tunable sizes, enabling the observation of quantum interference effects at room temperature, supported by tight-binding calculations.

Findings

Observation of Fabry-Perot resonances in graphene nanoconstrictions

Resonance energies depend on constriction size

Quantum interference effects persist at room temperature

Abstract

We have realized nanometer size constrictions in ballistic graphene nanoribbons grown on sidewalls of SiC mesa structures. The high quality of our devices allows the observation of a number of electronic quantum interference phenomena. The transmissions of Fabry-Perot like resonances were probed by in-situ transport measurements at various temperatures. The energies of the resonances are determined by the size of the constrictions which can be controlled precisely using STM lithography. The temperature and size dependence of the measured conductances are in quantitative agreement with tight-binding calculations. The fact that these interference effects are visible even at room temperature makes the reported devices attractive as building blocks for future carbon based electronics.