Tunable ground-state degeneracies in double quantum dots

Hong Yi Chen, Jaime Zaratiegui Garcia, Tapash Chakraborty, Pekka Pietilainen

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Abstract

We have studied the effect of electron-electron interactions on planar double quantum dots subjected to an external magnetic field. Contrary to all other earlier works on similar systems, our accurate results for the energy levels and the dipole-allowed transition energies reveal the absence of singlet-triplet crossing (due to electron correlations only) in the case when the dots occupy only two electrons. For a larger number of electrons, we find the expected crossing of the energy levels. The corresponding far-infrared optical absorption spectra show the effect of electronic interactions as well as the underlying symmetries of these systems. The hyper-exponential increase of the exchange energy, as derived in our model, would facilitate the coherent control of the spin states in a double dot, as proposed in recent experiments.

Original languageEnglish
Pages (from-to)2834-2838
Number of pages5
JournalPhysica E: Low-Dimensional Systems and Nanostructures
Volume40
Issue number8
DOIs
Publication statusPublished - 2008 Jun 1
Externally publishedYes

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Keywords

  • Gaussian confinement
  • Quantum dot
  • Single-triplet

ASJC Scopus subject areas

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

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