DNA nucleotide-specific modulation of \mu A transverse edge currents through a metallic graphene nanoribbon with a nanopore

TL;DR

This paper proposes a graphene nanoribbon-based device for DNA sequencing that detects nucleotides by their specific modulation of edge currents, offering a potentially higher signal-to-noise ratio than existing methods.

Contribution

It introduces a novel device concept utilizing edge current modulation in ZGNRs for DNA nucleotide detection, differing from traditional tunneling current approaches.

Findings

Unique conductance changes for each nucleotide detected

Edge current modulation is of the order of microamperes at 0.1 V bias

Device concept applicable to other nanowire systems

Abstract

We propose two-terminal devices for DNA sequencing which consist of a metallic graphene nanoribbon with zigzag edges (ZGNR) and a nanopore in its interior through which the DNA molecule is translocated. Using the nonequilibrium Green functions combined with density functional theory, we demonstrate that each of the four DNA nucleotides inserted into the nanopore, whose edge carbon atoms are passivated by either hydrogen or nitrogen, will lead to a unique change in the device conductance. Unlike other recent biosensors based on transverse electronic transport through DNA nucleotides, which utilize small (of the order of pA) tunneling current across a nanogap or a nanopore yielding a poor signal-to-noise ratio, our device concept relies on the fact that in ZGNRs local current density is peaked around the edges so that drilling a nanopore away from the edges will not diminish the conductance. Inserting a DNA nucleotide into the nanopore affects the charge density in the surrounding area, thereby modulating edge conduction currents whose magnitude is of the order of \mu A at bias voltage ~ 0.1 V. The proposed biosensor is not limited to ZGNRs and it could be realized with other nanowires supporting transverse edge currents, such as chiral GNRs or wires made of two-dimensional topological insulators.