Correlation Induced Inhomogeneity in Circular Quantum Dots

TL;DR

This study uses quantum Monte Carlo methods to explore how electron correlations induce inhomogeneity in circular quantum dots at intermediate densities, revealing smooth transitions and enhanced inhomogeneities due to interactions.

Contribution

It demonstrates that electron-electron correlations in confined systems cause gradual inhomogeneity formation without sharp phase transitions.

Findings

Correlation induces ring and angular modulations in electron density.

Inhomogeneities are significantly enhanced by interactions.

No sharp transition observed in the intermediate density range.

Abstract

Properties of the "electron gas" - in which conduction electrons interact by means of Coulomb forces but ionic potentials are neglected - change dramatically depending on the balance between kinetic energy and Coulomb repulsion. The limits are well understood. For very weak interactions (high density), the system behaves as a Fermi liquid, with delocalized electrons. In contrast, in the strongly interacting limit (low density), the electrons localize and order into a Wigner crystal phase. The physics at intermediate densities, however, remains a subject of fundamental research. Here, we study the intermediate-density electron gas confined to a circular disc, where the degree of confinement can be tuned to control the density. Using accurate quantum Monte Carlo techniques, we show that the electron-electron correlation induced by an increase of the interaction first smoothly causes rings, and then angular modulation, without any signature of a sharp transition in this density range. This suggests that inhomogeneities in a confined system, which exist even without interactions, are significantly enhanced by correlations.