Few-electron eigenstates of concentric double quantum rings

TL;DR

This paper investigates the behavior of few-electron states in concentric double quantum rings under magnetic fields, revealing charge localization, state transitions, and electron correlation effects using exact diagonalization.

Contribution

It provides a detailed analysis of magnetic field effects on electron localization, charge redistribution, and correlations in double quantum rings, including the connection to fractional Aharonov-Bohm oscillations.

Findings

Magnetic field suppresses tunnel coupling, localizing electrons.

Charge redistribution affects Aharonov-Bohm period.

Electron correlations evolve into a Wigner molecule at high fields.

Abstract

Few-electron eigenstates confined in coupled concentric double quantum rings are studied by the exact diagonalization technique. We show that the magnetic field suppresses the tunnel coupling between the rings localizing the single-electron states in the internal ring, and the few-electron states in the external ring. The magnetic fields inducing the ground-state angular momentum transitions are determined by the distribution of the electron charge between the rings. The charge redistribution is translated into modifications of the fractional Aharonov-Bohm period. We demonstrate that the electron distribution can be deduced from the cusp pattern of the chemical potentials governing the single-electron charging properties of the system. The evolution of the electron-electron correlations to the high field limit of a classical Wigner molecule is discussed.