Carbon Nanoelectronics: Unzipping Tubes into Graphene Ribbons

Abstract

We report on the transport properties of novel carbon nanostructures made of partially unzipped carbon nanotubes, which can be regarded as a seamless junction of a tube and a nanoribbon. We find that graphene nanoribbons act at certain energy ranges as a perfect valley filters for carbon nanotubes, with the maximum possible conductance. Our results show that a partially unzipped carbon nanotube is a magnetoresistive device, with a very large value of the magnetoresistance. We explore the properties of several structures combining nanotubes and graphene nanoribbons, demonstrating that they behave as optimal contacts for each other, and opening a new route for the design of mixed graphene/nanotube devices.

Grain boundaries with octagonal defects in graphene nanoribbons and nanotubes

“…Of course, we have checked that this choice does not change our results qualitatively with respect to the band structure and the magnetization. It confirms previous findings 29,31 that the magnetization effects and general character of the bands are robust with respect to the value of U .…”

Electronic and Magnetic Properties of Partially Open Carbon Nanotubes

“…Among them, chemical functionalization/doping and the application of external eletric/magnetic fields are known as being practically viable approaches to tailoring the electrical properties of CNTs 5,7,12,13,14,15 . In general, carbon-based systems are promising candidates for spin-based applications such as spin-qubits and spintronics 11,12,16,17,18,19,20 ; they are believed to have exceptionally long spin coherence times because of the absence of the nuclear spin in the carbon atom and very weak spin-orbit interactions. Therefore, in addition to their unique electrical properties, designing and modulating the spin injection and spin transport in CNTs have drawn heightened attention.…”

Interplay between bending and stretching in carbon nanoribbons

“…8 With the same technique, a new class of carbon-based nanostructures, which combine nanoribbons and nanotubes, has been introduced in order to obtain magnetoresistive devices. 9 Within this scenario we frame the present investigation, addressed to improve our fundamental understanding of the bending properties of a one-atom thick carbon sheet. The main goal is twofold: (i) to draw a thorough theoretical picture on bending, fully exploiting the elasticity theory and providing an atomistic quantitative estimation of the corresponding bending rigidity; (ii) to prove that the bending process of a carbon nanoribbon is always associated with the emergence of a (small) stretching, particularly close to the edges.…”