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Phys. Rev. B 73, 075315 (2006) [9 pages]

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

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T. Stopa1,2, B. Szafran1,2, M. B. Tavernier1, and F. M. Peeters1
1Departement Fysica, Universiteit Antwerpen, Groenenborgerlaan 171, B-2020 Antwerpen, Belgium
2Faculty of Physics and Applied Computer Science, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Kraków, Poland

Received 2 June 2005; revised 28 October 2005; published 10 February 2006

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 nonmonotonically 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.

© 2006 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevB.73.075315
DOI:
10.1103/PhysRevB.73.075315
PACS:
73.21.La, 73.43.−f, 71.10.Pm