Conductance signatures of electron confinement induced by strained nanobubbles in graphene

TL;DR

This study explores how strained nanobubbles in graphene nanoribbons influence electronic conductance, revealing electron confinement effects and Fano resonances caused by pseudomagnetic fields and mode interactions.

Contribution

It provides a detailed simulation-based analysis of conductance modifications and electron confinement in graphene nanoribbons induced by nanobubbles, highlighting the role of pseudomagnetic fields.

Findings

Low-energy electrons are confined by nanobubbles.

Pseudomagnetic fields shape conductance signatures.

Fano resonances emerge from mode coupling.

Abstract

We investigate the impact of strained nanobubbles on the conductance characteristics of graphene nanoribbons using a combined molecular dynamics - tight-binding simulation scheme. We describe in detail how the conductance, density of states, and current density of zigzag or armchair graphene nanoribbons are modified by the presence of a nanobubble. In particular, we establish that low-energy electrons can be confined in the vicinity or within the nanobubbles by the delicate interplay between the pseudomagnetic field pattern created by the shape of the bubble, mode mixing, and substrate interaction. The coupling between confined evanescent states and propagating modes can be enhanced under different clamping conditions, which translates into Fano resonances in the conductance traces.