Regimes of correlated hopping via a two-site interacting chain

TL;DR

This paper theoretically investigates inelastic electron transport through a two-impurity chain, revealing a novel two-electron hopping regime caused by intersite Coulomb interactions, which affects current-voltage behavior.

Contribution

It introduces and analyzes a new transport regime where two-electron hops dominate due to Coulomb blockade effects, expanding understanding of correlated electron transport.

Findings

Identification of a two-electron hopping transport regime

Observation of an additional step in I(V) characteristics

Demonstration of Coulomb interaction effects on transport regimes

Abstract

Inelastic transport of electrons through a two-impurity chain is studied theoretically with account of intersite Coulomb interaction, U. Both limits of ohmic transport (at low bias) and strongly non-ohmic transport (at high bias) are considered. We demonstrate that correlations, induced by a finite U, in conjunction with conventional Hubbard correlations, give rise to a distinct transport regime, with current governed by two-electron hops. This regime realizes when a single-electron hop onto the chain and a single-electron hop out of the chain are both ``blocked'' due to the finite U, so that conventional correlated sequential transport is impossible. The regime of two-electron hops manifests itself in the form of an additional step in the current-voltage characteristics, I(V).