Effect of finite Coulomb interaction on full counting statistics of electronic transport through single-molecule magnet

TL;DR

This paper investigates how finite Coulomb interaction influences the full counting statistics and shot noise in electronic transport through a single-molecule magnet, revealing symmetry properties and conditions for super-Poissonian noise.

Contribution

It provides a detailed analysis of the effects of finite Coulomb interaction on FCS and shot noise, highlighting differences from the infinite interaction limit and experimental observability.

Findings

Finite U causes symmetric gate-voltage dependence in FCS when electrodes are interchanged.

Super-Poissonian shot noise appears under specific coupling asymmetries and finite U.

The mechanism involves competition between fast and slow transport channels.

Abstract

We study the full counting statistics (FCS) in a single-molecule magnet (SMM) with finite Coulomb interaction $U$. For finite $U$ the FCS, differing from $U\rightarrow \infty $, shows a symmetric gate-voltage-dependence when the coupling strengths with two electrodes are interchanged, which can be observed experimentally just by reversing the bias-voltages. Moreover, we find that the effect of finite $U$ on shot noise depends on the internal level structure of the SMM and the coupling asymmetry of the SMM with two electrodes as well. When the coupling of the SMM with the incident-electrode is stronger than that with the outgoing-electrode, the super-Poissonian shot noise in the sequential tunneling regime appears under relatively small gate-voltage and relatively large finite $U$, and dose not for $U\rightarrow \infty $; while it occurs at relatively large gate-voltage for the opposite coupling case. The formation mechanism of super-Poissonian shot noise can be qualitatively attributed to the competition between fast and slow transport channels.