Effective charge-spin models for quantum dots

Article

关键词: ELECTRON-ELECTRON INTERACTIONS;    T-J MODEL;    CUPRATE SUPERCONDUCTORS;    CORRELATED ELECTRONS;    NONLINEAR TRANSPORT;    HUBBARD RING;    CUO2 PLANES;    PERTURBATION;    STATES;    NANOSTRUCTURES;   

DOI  :  10.1103/PhysRevB.54.4936

来源: SCIE

【 摘 要 】

It is shown that at low densities, quantum dots with few electrons may be mapped onto effective charge-spin models for the low-energy eigenstates. This is justified by defining a lattice model based on a many-electron pocket-state basis in which electrons are localized near their classical ground-state positions. The equivalence to a single-band Hubbard model is then established lending to a charge-spin (t-J-V) model which for most geometries reduces to a spin (Heisenberg) model. The method is refined to include processes which involve cyclic rotations of a ''ring'' of neighboring electrons. This is achieved by introducing intermediate lattice points and the importance of ring processes relative to pair-exchange processes is investigated using high-order degenerate perturbation theory and the WKB approximation. The energy spectra are computed from the effective models for specific cases and compared with exact results and other approximation methods.

【 授权许可】

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