Negative differential conductance and super-Poissonian shot noise in single-molecule magnet junctions

TL;DR

This paper investigates how electron transport in single-molecule magnet junctions exhibits negative differential conductance and super-Poissonian shot noise, which can be tuned by gate voltage and electrode spin polarization, revealing complex transport mechanisms.

Contribution

It provides a detailed analysis of negative differential conductance and shot noise in single-molecule magnet junctions, highlighting the influence of electrode spin polarization and transport channel competition.

Findings

Negative differential conductance can be tuned by gate voltage.

Super-Poissonian shot noise depends on electrode spin polarization.

Transport mechanisms involve competition between fast and slow channels.

Abstract

Molecular spintroinic device based on a single-molecule magnet is one of the ultimate goals of semiconductor nanofabrication technologies. It is thus necessary to understand the electron transport properties of a single-molecule magnet junction. Here we study the negative differential conductance and super-Poissonian shot noise properties of electron transport through a single-molecule magnet weakly coupled to two electrodes with either one or both of them being ferromagnetic. We predict that the negative differential conductance and super-Poissonian shot noise, which can be tuned by a gate voltage, depend sensitively on the spin polarization of the source and drain electrodes. In particular, the shot noise in the negative differential conductance region can be enhanced or decreased originating from the different formation mechanisms of negative differential conductance. The effective competition between fast and slow transport channels is responsible for the observed negative differential conductance and super-Poissonian shot noise. In addition, we further discuss the skewness and kurtosis properties of transport current in the super-Poissonian shot noise regions. Our findings suggest a tunable negative differential conductance molecular device, and the predicted properties of high-order current cumulants are very interesting for a better understanding of electron transport through single-molecule magnet junctions.