Artificial molecular quantum rings: Spin density functional theory calculations

TL;DR

This study uses spin density functional theory to analyze the electronic ground states of coupled quantum rings, revealing new phases and tunneling-induced phase transitions at smaller energies compared to quantum dots.

Contribution

It introduces a detailed analysis of coupled quantum rings, highlighting new phases and phase transitions influenced by tunneling effects, extending understanding beyond quantum dot systems.

Findings

Identification of new phases in larger rings

Tunneling-induced phase transitions occur at lower energies

Recovery of quantum dot results for small ring radius

Abstract

The ground states of artificial molecules made of two vertically coupled quantum rings are studied within the spin density functional theory for systems containing up to 13 electrons. Quantum tunneling effects on the electronic structure of the coupled rings are analyzed. For small ring radius, our results recover those of coupled quantum dots. For intermediate and large ring radius, new phases are found showing the formation of new diatomic artificial ring molecules. Our results also show that the tunneling induced phase transitions in the coupled rings occur at much smaller tunneling energy as compared to those for coupled quantum dot systems.