Partially unzipped carbon nanotubes as magnetic field sensors

TL;DR

This study investigates how partially unzipped carbon nanotubes connected to graphene nanoribbons can function as magnetic field sensors by analyzing conductance changes under external magnetic fields using Green's function techniques.

Contribution

It introduces a novel application of partially unzipped CNT-GNR junctions as magnetic sensors and explores their conductance behavior under magnetic fields, highlighting unique electronic features.

Findings

Magnetic field suppresses conductance at low energies in CNT regions.

Zero-field conductance shows a sharp dip near the Dirac point.

Both junction types can be effectively used as magnetic sensors.

Abstract

The conductance, $G(E)$, through graphene nanoribbons (GNR) connected to a partially unzipped carbon nanotube (CNT) is studied in the presence of an external magnetic field applied parallel to the long axis of the tube by means of non-equilibrium Green's function technique. We consider (z)igzag and (a)rmchair CNTs that are partially unzipped to form aGNR/zCNT/aGNR or zGNR/aCNT/zGNR junctions. We find that the inclusion of a longitudinal magnetic field affects the electronic states only in the CNT region, leading to the suppression of the conductance at low energies. Unlike previous studies, for the zGNR/aCNT/zGNR junction in zero field, we find a sharp dip in the conductance as the energy approaches the Dirac point and we attribute this non-trivial behavior to the peculiar band dispersion of the constituent subsystems. We demonstrate that both types of junctions can be used as magnetic field sensors.