Electron correlations in a C20 fullerene cluster |
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Authors: | R López-Sandoval G M Pastor |
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Institution: | (1) Instituto Potosino de Investigación Científica y Tecnológica, Camino a la presa San José 2055, 78216 San Luis Potosí, Mexico;(2) Laboratoire de Physique Quantique, Centre National de la Recherche Scientifique, Université Paul Sabatier, 118 route de Narbonne, 31062 Toulouse, France;(3) Laboratoire de Nanophysique Magnétisme et Optoélectronique, Institut National des Sciences Appliquées, 135 avenue de Rangueil, 31062 Toulouse, France |
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Abstract: | The ground-state properties of C20 fullerene clusters
are determined in the framework of the Hubbard model by using
lattice density-functional theory (LDFT) and
scaling approximations to the interaction-energy functional.
Results are given for the ground-state energy, kinetic and Coulomb
energies, local magnetic moments, and charge-excitation
gap, as a function of the Coulomb repulsion U/t and for
electron or hole doping δ close to half-band filling
(|δ| ≤1). The role of electron correlations is
analyzed by comparing the LDFT results with fully unrestricted
Hartree-Fock (UHF) calculations which take into account
possible noncollinear arrangements of the local spin-polarizations.
The consequences of the spin-density-wave symmetry breaking,
often found in UHF, and the implications of this
study for more complex fullerene structures are discussed. |
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Keywords: | 36 40 Cg Electronic and magnetic properties of clusters 71 10 Fd Lattice fermion models (Hubbard model etc ) 73 22 -f Electronic structure of nanoscale materials: clusters nanoparticles nanotubes and nanocrystals |
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