2004/08/09 by M. Marlo-Helle, A. Harju, Ari Harju +1 · 1 citation
Engineering · Physics and Astronomy · #Photonic and Optical Devices #Quantum optics and atomic interactions #Semiconductor Quantum Structures and Devices #cond-mat.mes-hall
paper · pdf · doi:10.1016/j.physe.2004.08.065
published as Physica E 26, 286 (2005) · 4 pages, 3 figures, QD2004 conference paper, accepted in Physica E
arxiv created 2004/08/09 · openalex publication_date 2004/12/16 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
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 ω+ 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.