  The fabrication of nanopores in atomically-thin graphene has recently been
achieved and translocation of DNA has been demonstrated. Taken together with an
earlier proposal to use graphene nanogaps for the purpose of DNA sequencing,
this approach can resolve the technical problem of achieving single-base
resolution in electronic nucleobase detection. We have theoretically evaluated
the performance of a graphene nanogap setup for the purpose of whole-genome
sequencing, by employing density functional theory and the non-equilibrium
Green's function method to investigate the transverse conductance properties of
nucleotides inside the gap. In particular, we determined the electrical
tunneling current variation at finite bias due to changes in the nucleotides
orientation and lateral position. Although the resulting tunneling current is
found to fluctuate over several orders of magnitudes, a distinction between the
four DNA bases appears possible, thus ranking the approach promising for rapid
whole-genome sequencing applications.
