Ground state instability in spin polarization for electrons confined in two-dimensional square quantum dots

Yhuki Negishi, Masamu Ishizuki, Takuma Okunishi, Kyozaburo Takeda

    研究成果: Article

    2 引用 (Scopus)

    抄録

    We present a theoretical study of the ground state electronic structure and the spin polarization for four electrons confined in two-dimensional (2D) square quantum dots (SQDs). We employ standard mean field theory (MFT) approaches using the unrestricted Hartree-Fock (UHF) and density functional theory calculations. The resonant UHF configuration interaction (res-UHF CI) calculation was also performed in order to incorporate the electron correlation more intuitively. The MFT ground state is expected to be spin-polarized when SQDs have a small confinement length L or aspect ratio δ = L x/Ly = 1, in agreement with Hund's rule. In contrast, the spin-unpolarized ground state singlet is expected in all in other SQDs. Thus, the MFT calculations produce the anti-Hund state, where the spin-density wave forms having the zero of the total spin, even though the SQD has the point group symmetry D4h. However, the res-UHF CI calculation restores the geometrical symmetry in the resulting ground state when the Coulomb interaction is strengthened. Nevertheless, the res-UHF CI ground state maintains the zero total spin. Thus, ground state instability is expected in the spin-polarization of the SQD system, which eventually violates Hund's rule in accordance with the Coulomb interaction.

    元の言語English
    記事番号085001
    ジャーナルJapanese Journal of Applied Physics
    50
    発行部数8 PART 1
    DOI
    出版物ステータスPublished - 2011 8

    Fingerprint

    Spin polarization
    Ground state
    Semiconductor quantum dots
    quantum dots
    Mean field theory
    ground state
    Electrons
    polarization
    electrons
    configuration interaction
    Crystal symmetry
    Coulomb interactions
    Spin density waves
    Point groups
    Electron correlations
    symmetry
    Electronic structure
    Density functional theory
    Aspect ratio
    aspect ratio

    ASJC Scopus subject areas

    • Engineering(all)
    • Physics and Astronomy(all)

    これを引用

    Ground state instability in spin polarization for electrons confined in two-dimensional square quantum dots. / Negishi, Yhuki; Ishizuki, Masamu; Okunishi, Takuma; Takeda, Kyozaburo.

    :: Japanese Journal of Applied Physics, 巻 50, 番号 8 PART 1, 085001, 08.2011.

    研究成果: Article

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