Tunneling conductance of graphene NIS junctions

TL;DR

This paper investigates the unique oscillatory tunneling conductance behavior in graphene NIS junctions, highlighting how it differs from conventional NIS junctions and proposing experimental tests.

Contribution

It reveals the oscillatory dependence of tunneling conductance on barrier strength in graphene NIS junctions and identifies conditions for maximum conductance.

Findings

Conductance oscillates with barrier strength in graphene NIS junctions.

Maximum zero-bias conductance occurs at finite barrier strength.

Oscillation amplitude depends on Fermi surface alignment.

Abstract

We show that in contrast to conventional normal metal-insulator-superconductor (NIS) junctions, the tunneling conductance of a NIS junction in graphene is an oscillatory function of the effective barrier strength of the insulating region, in the limit of a thin barrier. The amplitude of these oscillations are maximum for aligned Fermi surfaces of the normal and superconducting regions and vanishes for large Fermi surface mismatch. The zero-bias tunneling conductance, in sharp contrast to its counterpart in conventional NIS junctions, becomes maximum for a finite barrier strength. We also suggest experiments to test these predictions.