Electronic structure of few-electron concentric double quantum rings

TL;DR

This paper investigates the electronic structure of few-electron concentric double quantum rings, revealing how inter-ring distance influences electron localization, energy spectra, and the formation of strongly correlated states.

Contribution

It provides a detailed analysis of how inter-ring coupling affects electronic configurations and energy spectra in double quantum rings, highlighting the transition from isolated to entangled states.

Findings

Inter-ring coupling signatures are identified in the addition energy spectrum.

Electron localization varies with inter-ring distance, affecting energy structure.

Intermediate distances lead to quasi-degenerate and strongly correlated electron states.

Abstract

The ground state structure of few-electron concentric double quantum rings is investigated within the local spin density approximation. Signatures of inter-ring coupling in the addition energy spectrum are identified and discussed. We show that the electronic configurations in these structures can be greatly modulated by the inter-ring distance: At short and long distances the low-lying electron states localize in the inner and outer rings, respectively, and the energy structure is essentially that of an isolated single quantum ring. However, at intermediate distances the electron states localized in the inner and the outer ring become quasi-degenerate and a rather entangled, strongly-correlated system is formed.