2008/07/31 by Ioan Bâldea, Ioan Baldea, Lorenz S. Cederbaum +3 · 2 citations
Engineering · Materials Science · Physics and Astronomy · #Molecular Junctions and Nanostructures #Quantum Dots Synthesis And Properties #Quantum and electron transport phenomena #cond-mat.str-el
paper · pdf · doi:10.1140/epjb/e2009-00150-3
published as Eur. Phys. J. B 69, 251 (2009)
arxiv created 2009/03/26 · openalex publication_date 2009/05/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We report detailed results on ionization in metallic quantum--dot (QD) nanorings described by the extended Hubbard model at half filling obtained by exact numerical diagonalization. In spite of very strong electron correlations, the ionization spectra are astonishingly scarce. We attribute this scarcity to a hidden quasi--symmetry, generalizing thereby similar results on optical absorption recently reported [I. Baldea and L. S. Cederbaum, \prb \bf 75, 125323 (2007); \bf 77, 165339 (2008)]. Numerical results indicate that this hidden quasi--symmetry of the extended Hubbard model does not evolve into a true (hidden) symmetry but remains a quasi--symmetry in the case of the restricted Hubbard model as well. Based on the observation on the number of significant ionization signals per each spatial symmetry, we claim the existence of a one--to--one map between the relevant ionization signals of the correlated half-filled nanorings and the one-hole and two-hole--one-particle processes possible in the noninteracting case. Similar to the case of optical absorption, numerous avoided crossings (anticrossings) are present in the ionization spectra, which often involve more than two states. The present results demonstrate that ionization could be a useful tool to study electron correlations in metallic QD--nanoarrays, providing information that is complementary to optical absorption.