Tunneling states in graphene heterostructures consisting of two different graphene superlattices

TL;DR

This paper theoretically investigates electronic transport in graphene heterostructures made of two different superlattices, revealing an unusual tunneling state that enhances conductance and suppresses noise near specific energies.

Contribution

It introduces the concept of a tunneling state within forbidden gaps in graphene heterostructures and derives the impedance matching condition for its occurrence.

Findings

Unusual tunneling state occurs inside forbidden gaps.

Electronic conductance is greatly enhanced near the tunneling state.

Fano factor is strongly suppressed near the tunneling state.

Abstract

We have theoretically investigated the properties of electronic transport in graphene heterostructures, which are consisted of two different graphene superlattices with one-dimensional periodic potentials. It is found that such heterostructures possess an unusual tunneling state occurring inside the original forbidden gaps, and the electronic conductance is greatly enhanced and Fano factor is strongly suppressed near the energy of the tunneling state. Finally we present the matching condition of the impedance of the pseudospin wave for occuring the tunneling state by using the Bloch-wave expansion method.