Spin transitions in semiconductor quantum rings

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Autor/in:
Erscheinungsjahr:
2010
Medientyp:
Text
Schlagworte:
  • Gallium arsenide
  • Nanorings
  • Droplet epitaxy
  • Semiconductor Quantum Dots
  • Semiconductor Quantum Wells
  • Gallium Arsenide
  • Gallium arsenide
  • Nanorings
  • Droplet epitaxy
  • Semiconductor Quantum Dots
  • Semiconductor Quantum Wells
  • Gallium Arsenide
Beschreibung:
  • We adopt the path integral Monte Carlo method to accurately resolve the total spin of the ground state of electrons confined in a quantum ring with different geometries. Using this method, an evaluation of the ground state of three electrons in a ring shows a spin transition to the fully polarized state by increasing the radius and thereby enhancing the Coulomb interaction. The total spin of the ground state is determined by the mutual interplay of confinement and electron-electron interaction. An analysis of the four-electron ring demonstrates that in this case no spin transitions take place. Furthermore, the effect of geometric distortion of the ring on its ground state has been investigated. Elliptically deforming the ring breaks the symmetry of the system and leads to the removal of orbital degeneracy. For strong distortion the splitting between hybridized states is sufficient to overcome the exchange-energy saving associated with a higher spin state. We have found that this effect removes the polarization of three electrons. Even in a four-electron ring the ground state is forced by the distortion to be unpolarized and thus suppressing the Hund's rule ground state.
Lizenz:
  • info:eu-repo/semantics/restrictedAccess
Quellsystem:
Forschungsinformationssystem der UHH

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oai:www.edit.fis.uni-hamburg.de:publications/649de5fc-a811-439d-8765-48fd6739942a