Theory of shot noise in single-walled metallic carbon nanotubes weakly coupled to nonmagnetic and ferromagnetic leads

TL;DR

This paper provides a theoretical analysis of shot noise, conductance, and tunnel magnetoresistance in single-walled metallic carbon nanotubes with different lead types, revealing periodic behaviors linked to electron charging.

Contribution

It introduces a detailed theoretical framework for understanding shot noise and magnetoresistance in nanotubes with ferromagnetic and nonmagnetic contacts, highlighting the effects of contact type.

Findings

Four-fold periodicity in differential conductance and TMR

Periodic behavior observed in Fano factor and TMR

Impact of ferromagnetic contacts on transport properties

Abstract

We present theoretical study of shot noise in single wall metallic carbon nanotubes weakly coupled to either nonmagnetic or ferromagnetic leads. Using the real-time diagrammatic technique, we calculate the current, Fano factor and tunnel magnetoresistance in the sequential tunneling regime. It is shown that the differential conductance displays characteristic four-fold periodicity, indicating single-electron charging. Such a periodicity is also visible in tunnel magnetoresistance of the system as well as in the Fano factor. The present studies elucidate the impact of ferromagnetic (vs. nonmagnetic) contacts on the transport characteristics under consideration.