On the metallic behavior of Co clusters

The role of structure in the nonmetal-metal transition of Co clusters is investigated by performing calculations for different symmetries: hexahedral, octahedral and decahedral. This transition occurs when the density of states at the Fermi level exceeds l/kBT and the discrete energy levels begin to...

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Detalles Bibliográficos
Autores principales: Aguilera-Granja, F., Montejano-Carrizales, J.M., Guevara, J., Llois, A.M.
Formato: JOUR
Materias:
A. Insulators
A. Metals
A. Nanostructures
Approximation theory
Band structure
Cobalt
Computational methods
Electronic density of states
Electronic structure
Fermi level
Nanostructured materials
Phase transitions
Cobalt clusters
Hubbard tight-binding Hamiltonian
Electric insulating materials
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00381098_v113_n3_p147_AguileraGranja
Aporte de:
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
Descripción
Sumario:The role of structure in the nonmetal-metal transition of Co clusters is investigated by performing calculations for different symmetries: hexahedral, octahedral and decahedral. This transition occurs when the density of states at the Fermi level exceeds l/kBT and the discrete energy levels begin to form a quasi-continuous band. The electronic structure is calculated including spd orbitals and spillover effects in a Hubbard Hamiltonian solved within the unrestricted Hartree-Fock approximation. We find that in small clusters (N ≤ 40) the metallic behavior is strongly related to the geometrical structure of the cluster. We compare our results with those coming out of a simple Friedel's model. © 1999 Elsevier Science Ltd. All rights reserved.

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