Fano resonances in hexagonal zigzag graphene rings under external magnetic flux

TL;DR

This paper investigates how external magnetic flux influences Fano resonances in hexagonal zigzag graphene rings, revealing the role of localized states and strain effects on transport properties.

Contribution

It introduces a detailed analysis of magnetic flux-induced Fano resonances in graphene rings, including strain effects, using tight-binding and Green's function methods.

Findings

Magnetic field induces Fano resonances from localized states.

Strain shifts resonance positions and can create new resonances.

Localized states are robust and observable in transport measurements.

Abstract

We study transport properties of hexagonal zigzag graphene quantum rings connected to semi-infinite nanoribbons. Open two-fold symmetric structures support localized states that can be traced back to those existing in the isolated six-fold symmetric rings. Using a tight-binding Hamiltonian within the Green's function formalism, we show that an external magnetic field promotes these localized states to Fano resonances with robust signatures in transport. Local density of states and current distributions of the resonant states are calculated as a function of the magnetic flux intensity. For structures on corrugated substrates we analyze the effect of strain by including an out-of-plane centro-symmetric deformation in the model. We show that small strains shift the resonance positions without further modifications, while high strains introduce new ones.