Transport through normal metal - graphene contacts

TL;DR

This paper investigates the conductance properties of zigzag graphene interfaces with normal metals, revealing how conductance depends on energy, junction length, and interface resistance, with implications for electronic transport in graphene-based devices.

Contribution

It introduces a detailed tight-binding analysis of NGN junctions, highlighting the role of evanescent and propagating modes in conductance behavior at different energies.

Findings

Conductance at the Dirac point is governed by evanescent modes and inversely related to junction length.

Away from the Dirac point, propagating modes dominate conductance.

High interface resistance does not always prevent ideal transmission due to Fabry-Perot resonances.

Abstract

Conductance of zigzag interfaces between graphene sheet and normal metal is investigated in the tight-binding approximation. Boundary conditions, valid for a variety of scattering problems, are constructed and applied to the normal metal -- graphene -- normal metal (NGN) junctions. At the Dirac point, the conductance is determined solely by the evanescent modes and is inversely proportional to the length of the junction. It is also independent on the interface resistance. Away from the Dirac point, the propagating modes' contribution dominates. We also observe that even in the junctions with high interface resistance, for certain modes, ideal transmission is possible via Fabry-Perot like resonances.