Mesoscopic Fluctuations of Elastic Cotunneling in Coulomb Blockaded Quantum Dots

TL;DR

This study investigates mesoscopic fluctuations in elastic cotunneling within Coulomb blockaded quantum dots, revealing distinct magnetic field scales and correlation behaviors compared to resonant tunneling, with implications for understanding quantum transport.

Contribution

It provides the first detailed measurement of mesoscopic fluctuations of elastic cotunneling in Coulomb blockaded quantum dots, highlighting differences from resonant tunneling phenomena.

Findings

Cotunneling fluctuations have a larger magnetic field scale than peak fluctuations.

Absence of weak localization effect in cotunneling valleys.

Cotunneling fluctuations are correlated over multiple valleys.

Abstract

We report measurements of mesoscopic fluctuations of elastic cotunneling in Coulomb blockaded quantum dots. Unlike resonant tunneling on Coulomb peaks, cotunneling in the valleys is sensitive to charging effects. We observe a larger magnetic field scale for the cotunneling (valley) fluctuations compared to the peaks, as well as an absence of "weak localization" (reduced conductance at B = 0) in valleys. Cotunneling fluctuations remain correlated over several valleys while peak conductance correlations decreases quickly.