Dependence of the vortex structure in quantum dots on the range of the inter-electron interaction

TL;DR

This paper explores how the vortex structure in quantum dots with three and five electrons evolves as the inter-electron interaction varies from Coulomb to contact potential, revealing non-monotonic behavior and vortex flips.

Contribution

It demonstrates the dependence of vortex structures on interaction range and shows vortex flips occur beyond the lowest Landau level approximation in quantum dots.

Findings

Vortex structure approaches Laughlin limit non-monotonically.

Vortex flips involve intermediate composite fermions.

Antivortices prevent giant vortex formation beyond LLL.

Abstract

The internal structure of a composite fermion is investigated for a two dimensional parabolic quantum dot containing three electrons. A Yukawa screened Coulomb interaction is assumed, which allows us to discuss the evolution of the electron-vortex correlations from the Coulomb interaction limit to the contact potential limit. The vortex structure approaches the Laughlin limit non-monotonically through the formation of intermediate composite fermions in which a flip of the spatial orientation of the vortices with respect to the position of the electrons is observed. Only when we limit ourselves to the lowest Landau level (LLL) approximation the flip appears through the formation of an intermediate giant vortex at specific values of the screening length. Beyond the LLL approximation antivortices appear in the internal structure of the intermediate composite fermions which prevent the nucleation of giant vortices. We also studied the system of five electrons and show that the mechanism of the flip of the vortex orientation found for three-electron system is reproduced for higher number of electrons.