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RESEARCH PRODUCT
Quantum rings for beginners: Energy spectra and persistent currents
Susanne ViefersM. ManninenPekka KoskinenP. Singha Deosubject
PhysicsCondensed Matter - Mesoscale and Nanoscale PhysicsCondensed matter physicsStrongly Correlated Electrons (cond-mat.str-el)Heisenberg modelFOS: Physical sciencesPersistent currentElectronic structureElectronCondensed Matter PhysicsAtomic and Molecular Physics and OpticsElectronic Optical and Magnetic MaterialsCondensed Matter - Strongly Correlated Electronssymbols.namesakeLuttinger liquidQuantum mechanicsMagnetic flux quantumMesoscale and Nanoscale Physics (cond-mat.mes-hall)symbolsHamiltonian (quantum mechanics)Quantumdescription
Theoretical approaches to one-dimensional and quasi-one-dimensional quantum rings with a few electrons are reviewed. Discrete Hubbard-type models and continuum models are shown to give similar results governed by the special features of the one-dimensionality. The energy spectrum of the many-body states can be described by a rotation-vibration spectrum of a 'Wigner molecule' of 'localized' electrons, combined with the spin-state determined from an effective antiferromagnetic Heisenberg Hamiltonian. The persistent current as a function of the magnetic flux through the ring shows periodic oscillations arising from the 'rigid rotation' of the electron ring. For polarized electrons the periodicity of the oscillations is always the flux quantum Phi_0. For nonpolarized electrons the periodicity depends on the strength of the effective Heisenberg coupling and changes from Phi_0 first to Phi_0/2 and eventually to Phi_0/N when the ring gets narrower.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2003-10-03 |