Tailoring coherent charge transport in graphene by deterministic defect generation

TL;DR

This paper demonstrates how deterministic defect engineering in graphene can induce phase-coherent charge transport, enabling the formation of electronic Fabry-Pérot cavities that support quantum resonances up to 30 K, advancing coherent electronic device design.

Contribution

It introduces a novel method of defect engineering in graphene to enable phase-coherent transport and resonant charge confinement, which was not previously achieved with such simplicity.

Findings

Defective graphene supports phase-matched charge carrier waves.

Fabry-Pérot resonances are observed as sheet resistance oscillations.

Coherent effects persist up to 30 K for both charge polarities.

Abstract

Harnessing the wave-nature of charge carriers in solid state devices, electron optics investigates and exploits coherent phenomena, in analogy with optics and photonics. Typically, this requires complex electronic devices leveraging macroscopically coherent charge transport in two-dimensional electron gases and superconductors. Here, collective coherent effects are induced in a simple counterintuitive architecture by defect engineering. Deterministically introduced lattice defects in graphene enable the phase coherent charge transport by playing the role of potential barriers, instead of scattering centres as conventionally considered. Thus, graphene preserves its quasi-ballistic quantum transport and can support phase-matched charge carrier waves. Based on this approach, multiple electronic Fabry-P\`erot cavities are formed by creating periodically alternating defective and pristine nano-stripes through low energy electron-beam irradiation. Indeed, defective stripes behave as partially reflecting mirrors and resonantly confine the charge carrier waves within the pristine areas, giving rise to Fabry-P\`erot resonant modes. These modes experimentally manifest as sheet resistance oscillations, as also confirmed by Landauer-B\"uttiker simulations. Moreover, these coherent phenomena survive up to 30 K for both polarities of charge carriers, contrarily to traditional monopolar electrostatically created Fabry-P\`erot interferometers. Our study positions defective graphene as an innovative platform for coherent electronic devices, with potential applications in nano and quantum technologies.