Interaction-Induced Strong Localization in Quantum Dots

TL;DR

This paper demonstrates that Coulomb blockade phenomena can serve as a direct experimental probe of the transition to strong electron correlation and localization in quantum dots, especially through changes in addition energy.

Contribution

It provides computational evidence linking the crossover from shell structure to Wigner crystal behavior with measurable addition energy changes in quantum dots.

Findings

Clear transition in addition energy from shell to Wigner crystal features

Crossover occurs near r_s ~ 20 for spin-polarized electrons

Localization signature detectable via Coulomb blockade experiments

Abstract

We argue that Coulomb blockade phenomena are a useful probe of the cross-over to strong correlation in quantum dots. Through calculations at low density using variational and diffusion quantum Monte Carlo (up to r_s ~ 55), we find that the addition energy shows a clear progression from features associated with shell structure to those caused by commensurability of a Wigner crystal. This cross-over (which occurs near r_s ~ 20 for spin-polarized electrons) is, then, a signature of interaction-driven localization. As the addition energy is directly measurable in Coulomb blockade conductance experiments, this provides a direct probe of localization in the low density electron gas.