Interaction-Induced Spin Polarization in Quantum Dots

TL;DR

This paper investigates how electron interactions induce spin polarization in quantum dots under high magnetic fields, revealing different behaviors in Landau levels and emphasizing the role of interactions in spin states.

Contribution

The study introduces a spin-density-functional theory approach to explain interaction-induced spin polarization effects in quantum dots, extending understanding beyond traditional models.

Findings

Landau level 0 shows spin-induced bimodality

Landau level 1 exhibits strong spin polarization suppressing bimodality

Interaction effects are crucial for explaining experimental data

Abstract

The electronic states of lateral many electron quantum dots in high magnetic fields are analyzed in terms of energy and spin. In a regime with two Landau levels in the dot, several Coulomb blockade peaks are measured. A zig-zag pattern is found as it is known from the Fock-Darwin spectrum. However, only data from Landau level 0 show the typical spin-induced bimodality, whereas features from Landau level 1 cannot be explained with the Fock-Darwin picture. Instead, by including the interaction effects within spin-density-functional theory a good agreement between experiment and theory is obtained. The absence of bimodality on Landau level 1 is found to be due to strong spin polarization.