Huge negative differential conductance in Au-H2 molecular nanojunctions

TL;DR

This paper reports large negative differential conductance in gold-hydrogen molecular nanojunctions and explains it using an asymmetrically coupled two-level system model, linking it to molecular excitations.

Contribution

It introduces an asymmetrically coupled TLS model that accurately explains peaklike features in differential conductance of Au-H2 nanojunctions, advancing understanding of molecular junction behavior.

Findings

Asymmetrically coupled TLS model fits experimental data well

Bound molecule excitation causes peaklike conductance features

Large negative differential conductance observed in experiments

Abstract

Experimental results showing huge negative differential conductance in gold-hydrogen molecular nanojunctions are presented. The results are analyzed in terms of two-level system (TLS) models: it is shown that a simple TLS model cannot produce peaklike structures in the differential conductance curves, whereas an asymmetrically coupled TLS model gives perfect fit to the data. Our analysis implies that the excitation of a bound molecule to a large number of energetically similar loosely bound states is responsible for the peaklike structures. Recent experimental studies showing related features are discussed within the framework of our model.