Electronic structure of multiple dots

M. Stopa, A. Vidan, T. Hatano, S. Tarucha, R. M. Westervelt

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

We calculate, via spin density functional theory (SDFT) and exact diagonalization, the eigenstates for electrons in a variety of external potentials, including double and triple dots. The SDFT calculations employ realistic wafer profiles and gate geometries and also serve as the basis for the exact diagonalization calculations. The exchange interaction J between electrons is the difference between singlet and triplet ground state energies and reflects competition between tunneling and the exchange matrix element, both of which result from overlap in the barrier. For double dots, a characteristic transition from singlet ground state to triplet ground state (positive to negative J) is calculated. For the triple dot geometry with 2 electrons we also find the electronic structure with exact diagonalization. For larger electron number (18 and 20) we use only SDFT. In contrast to the double dot case, the triple dot case shows a quasi-periodic fluctuation of J with magnetic field, which we attribute to periodic variations of the basis states in response to changing flux quanta threading the triple dot structure.

Original languageEnglish
Pages (from-to)616-619
Number of pages4
JournalPhysica E: Low-Dimensional Systems and Nanostructures
Volume34
Issue number1-2
DOIs
Publication statusPublished - 2006 Aug

Keywords

  • Quantum computation
  • Quantum dots
  • Spin density functional theory

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics

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