Itinerant ferromagnetism in the two-dimensional t-t′ Hubbard model

Using exact diagonalization techniques, the Hubbard model with hopping between nearest (t) and next-nearest neighbors (t′) is studied in a two-dimensional cluster with 4×4 sites. Within a range of values of t′ <0 and low densities, states with different total spin are degenerate in the noninterac...

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Autor principal: Arrachea, L.
Formato: JOUR
Materias:
acceleration
article
density
energy transfer
magnetism
mathematical model
molecular interaction
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_01631829_v62_n15_p10033_Arrachea
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
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spelling todo:paper_01631829_v62_n15_p10033_Arrachea2023-10-03T15:01:48Z Itinerant ferromagnetism in the two-dimensional t-t′ Hubbard model Arrachea, L. acceleration article density energy transfer magnetism mathematical model molecular interaction Using exact diagonalization techniques, the Hubbard model with hopping between nearest (t) and next-nearest neighbors (t′) is studied in a two-dimensional cluster with 4×4 sites. Within a range of values of t′ <0 and low densities, states with different total spin are degenerate in the noninteracting system. At a finite value of the Coulomb repulsion U, states with high spin are energetically favored and the ground state can be fully polarized. The behavior of the density of states differs from that obtained within the Hartree-Fock approximation. The low energy region of the density of states (DOS) for the majority spins remains weakly modified by U. Our results bring further support to the idea that itinerant ferromagnetism occurs in strongly correlated systems with high noninteracting DOS at the bottom of the band. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_01631829_v62_n15_p10033_Arrachea
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic acceleration
article
density
energy transfer
magnetism
mathematical model
molecular interaction
spellingShingle acceleration
article
density
energy transfer
magnetism
mathematical model
molecular interaction
Arrachea, L.
Itinerant ferromagnetism in the two-dimensional t-t′ Hubbard model
topic_facet acceleration
article
density
energy transfer
magnetism
mathematical model
molecular interaction
description Using exact diagonalization techniques, the Hubbard model with hopping between nearest (t) and next-nearest neighbors (t′) is studied in a two-dimensional cluster with 4×4 sites. Within a range of values of t′ <0 and low densities, states with different total spin are degenerate in the noninteracting system. At a finite value of the Coulomb repulsion U, states with high spin are energetically favored and the ground state can be fully polarized. The behavior of the density of states differs from that obtained within the Hartree-Fock approximation. The low energy region of the density of states (DOS) for the majority spins remains weakly modified by U. Our results bring further support to the idea that itinerant ferromagnetism occurs in strongly correlated systems with high noninteracting DOS at the bottom of the band.
format JOUR
author Arrachea, L.
author_facet Arrachea, L.
author_sort Arrachea, L.
title Itinerant ferromagnetism in the two-dimensional t-t′ Hubbard model
title_short Itinerant ferromagnetism in the two-dimensional t-t′ Hubbard model
title_full Itinerant ferromagnetism in the two-dimensional t-t′ Hubbard model
title_fullStr Itinerant ferromagnetism in the two-dimensional t-t′ Hubbard model
title_full_unstemmed Itinerant ferromagnetism in the two-dimensional t-t′ Hubbard model
title_sort itinerant ferromagnetism in the two-dimensional t-t′ hubbard model
url http://hdl.handle.net/20.500.12110/paper_01631829_v62_n15_p10033_Arrachea
work_keys_str_mv AT arracheal itinerantferromagnetisminthetwodimensionaltthubbardmodel
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