Supercondutividade e antiferromagnetismo em um modelo de Hubbard estendido
AUTOR(ES)
Gustavo Adolfo Lara Chaparrro
DATA DE PUBLICAÇÃO
1992
RESUMO
We study an extended Hubbard model, for the one band, square lattice case. We include both, the nearest neighbor direct and correlated hopping Coulomb terms. Within a generalized Hartree-Fock scheme we obtain superconductive solutions. Those solutions may be either non magnetic or antiferromagnetic (Néel-like). A necessary condition between parameters of the theory for stable superconductive solutions is obtained. The intra and jntersite Coulomb terms compete, modulated by the correlated hopping term, yielding a "covalent" pairing with partial intra and intersite pairing. For low density carriers, a non magnetic superconductive state is found, and for the nearly half filled band case the superconductive phase coexists with an antiferromagnetic phase. The solutions have broken electron-hole symmetry. For the "large" U case (intrasite Coulomb repulsion) equivalent to a linear approximation within our model, a superconductive state is not found
ASSUNTO(S)
supercondutores ceramicos supercondutividade
ACESSO AO ARTIGO
http://libdigi.unicamp.br/document/?code=vtls000042703Documentos Relacionados
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