Large negative transconductance in multilayer graphene: The role of intersubband scattering

TL;DR

This paper investigates how intersubband scattering affects the transport properties of multilayer graphene, revealing a large negative transconductance phenomenon that could enable novel electronic devices.

Contribution

It introduces a comprehensive multiband Boltzmann transport model accounting for intersubband scattering in multilayer graphene, highlighting the impact on conductivity and NTC.

Findings

Conductivity shows a sudden change at higher subband occupation

Large negative transconductance appears with carrier density variation

Intersubband scattering and density of states changes drive the phenomena

Abstract

We calculate the transport properties of multilayer graphene, considering the effect of multisubband scattering in a high density regime, where higher subbands are occupied by charge carriers. To calculate the conductivity of multilayer graphene, we use the coupled multiband Boltzmann transport theory while fully incorporating the multiband scattering effects. We show that the allowed scattering channels, screening effects, chiral nature of the electronic structure, and type of impurity scatterings determine the transport behavior of multilayer graphene. We find that the conductivity of multilayer graphene shows a sudden change when the carriers begin to occupy the higher subbands, and therefore a large negative transconductance (NTC) appears as the carrier density varies. These phenomena arise mostly from the intersubband scattering and the change in the density of states at the band touching density. Based on our results, it is possible to build novel devices utilizing the large NTC in multilayer graphene.