Counting Statistics in Nanoscale Junctions

TL;DR

This paper uses first-principles calculations to analyze current fluctuations up to third order in atomic-scale junctions, revealing oscillatory behavior and correlations between conductance and higher moments.

Contribution

It introduces a self-consistent method to compute higher-order current moments in nanoscale junctions from first principles, linking quantum correlations with transport properties.

Findings

Conductance and Fano factors oscillate with the number of carbon atoms.

Third-order Fano factor correlates positively with conductance.

Quantum correlations influence current fluctuations in atomic junctions.

Abstract

We present first-principles calculations for moments of the current up to the third order in atomic-scale junctions. The quantum correlations of the current are calculated using the current operator in terms of the wave functions obtained self-consistently within the static density-functional theory. We investigate the relationships of the conductance, the second, and the third moment of the current for carbon atom chains of various lengths bridging two metal electrodes in the linear and nonlinear regimes. The conductance, the second-, and the third-order Fano factors exhibit odd-even oscillation with the number of carbon atoms due to the full and half filled {\pi}* orbital near the Fermi levels. The third-order Fano factor and the conductance are positively correlated.