Tuning transport properties on graphene multi-terminal structures by mechanical deformations

TL;DR

This paper investigates how mechanical deformations influence transport properties in multi-terminal graphene structures, revealing that localized strains significantly affect resonant tunneling and extended deformations can enable nanoscale electronic waveguides.

Contribution

It provides a comparative analysis of strain effects on different graphene geometries and introduces potential applications in nanoscale waveguides.

Findings

Localized deformations impact resonant tunneling in hexagonal graphene flakes.

Extended deformations in triangular systems can serve as nanoscale waveguides.

Resonant transport is more sensitive to strain in certain geometries.

Abstract

Straintronic devices made of carbon-based materials have been pushed up due to the graphene high mechanical flexibility and the possibility of interesting changes in transport properties. Properly designed strained systems have been proposed to allow optimized transport responses that can be explored in experimental realizations. In multi-terminal systems, comparisons between schemes with different geometries are important to characterize the modifications introduced by mechanical deformations, specially if the deformations are localized at a central part of the system or extended in a large region. Then, in the present analysis, we study the strain effects on the transport properties of triangular and hexagonal graphene flakes, with zigzag and armchair edges, connected to three electronic terminals, formed by semi-infinite graphene nanoribbons. Using the Green's function formalism with circular renormalization schemes, and a single band tight-binding approximation, we find that resonant tunneling transport becomes relevant and is more affected by localized deformations in the hexagonal graphene flakes. Moreover, triangular systems with deformation extended to the leads, like longitudinal three-folded type, are shown as an interesting scenario for building nanoscale waveguides for electronic current.