3 research outputs found
Singlet-triplet oscillations and far-infrared spectrum of four-minima quantum-dot molecule
We study ground states and far-infrared spectra (FIR) of two electrons in
four-minima quantum-dot molecule in magnetic field by exact diagonalization.
Ground states consist of altering singlet and triplet states, whose frequency,
as a function of magnetic field, increases with increasing dot-dot separation.
When the Zeeman energy is included, only the two first singlet states remain as
ground states. In the FIR spectra, we observe discontinuities due to crossing
ground states. Non-circular symmetry induces anticrossings, and also an
additional mode above in the spin-triplet spectrum. In particular,
we conclude that electron-electron interactions cause only minor changes to the
FIR spectra and deviations from the Kohn modes result from the low-symmetry
confinement potential.Comment: 4 pages, 3 figures, QD2004 conference paper, accepted in Physica
Two-electron lateral quantum-dot molecules in a magnetic field
Laterally coupled quantum dot molecules are studied using exact
diagonalization techniques. We examine the two-electron singlet-triplet energy
difference as a function of magnetic field strength and investigate the
magnetization and vortex formation of two- and four-minima lateral quantum dot
molecules. Special attention is paid to the analysis of how the distorted
symmetry affects the properties of quantum-dot molecules.Comment: 18 pages, 26 figure