Tilted potential induced coupling of localized states in a graphene nanoconstriction

TL;DR

This study uses a scanning probe microscope to manipulate and analyze localized states in a graphene nanoconstriction, revealing how tip-induced potentials affect electron transport and state coupling.

Contribution

It introduces a method to visualize and control localized state coupling in graphene nanoconstrictions using a charged scanning probe tip.

Findings

Concentric halos in conductance maps indicate localized states.

Tip-induced potential modulates transmission resonances.

Localized state coupling is affected by potential gradients.

Abstract

We use the charged tip of a low temperature scanning probe microscope to perturb the transport through a graphene nanoconstriction. Maps of the conductance as a function of tip position display concentric halos, and by following the expansion of the halos with back-gate voltage we are able to identify an elongated domain over the nanoconstriction where they originate. Amplitude modulations of the transmission resonances are correlated with the gradient of the tip-induced potential and we analyze this in terms of modified coupling between localized states.