Conductance Suppression due to Correlated Electron Transport in Coupled Double-dots

TL;DR

This paper investigates how electrostatic interactions in coupled double-dots suppress conductance through correlated electron tunneling, revealing that single-electron movements in one dot influence tunneling rates in the other.

Contribution

The study introduces a master equation model that explains conductance suppression due to correlated electron transport in capacitively-coupled double-dots, aligning well with experimental results.

Findings

Conductance is significantly reduced when both double-dots are biased.

Single-electron tunneling in one dot affects tunneling in the other.

The model accurately predicts conductance suppression phenomena.

Abstract

The electrostatic interaction between two capacitively-coupled metal double-dots is studied at low temperatures. Experiments show that when the Coulomb blockade is lifted by applying appropriate gate biases to both double-dots, the conductance through each double-dot becomes significantly lower than when only one double-dot is conducting. A master equation is derived for the system and the results obtained agree well with the experimental data. The model suggests that the conductance lowering in each double-dot is caused by a single-electron tunneling in the other double-dot. Here, each double-dot responds to the instantaneous, rather than average, potentials on the other double-dot. This leads to correlated electron motion within the system, where the position of a single electron in one double-dot controls the tunneling rate through the other double-dot.