Whereas the t - J model has gained wide popularity among physicists as a model for high-TC superconductivity, its physical origin is not at all clear. In this communication we show that the Hubbard model with occupation-dependent hopping (t1 - t3 - U model), recently proposed to account for the relaxation of doubly-occupied orbitals, reduces, in a physically relevant parameter region, to an effective t - J - t′ model with no upper bound on the J/t ratio. Results of exact diagonalization studies on finite size systems demonstrate the equivalence between the t1 - t2 - t3 - U model with intermediate/large U and the t - J - t′ even for very large J/t ratio (up to 16). On the contrary, t - U and t - J models turn out to be equivalent to t - J - t′ model only for very small J values (J much smaller than t). Implications of the results on high-TC superconductivity are briefly discusses.

The orbital relaxation: A possible origin of t - J model with large J / A. Fortunelli;A. Painelli. - In: SOLID STATE COMMUNICATIONS. - ISSN 0038-1098. - 89(1994), pp. 771-773. [10.1016/0038-1098(94)90730-7]

The orbital relaxation: A possible origin of t - J model with large J

PAINELLI, Anna
1994

Abstract

Whereas the t - J model has gained wide popularity among physicists as a model for high-TC superconductivity, its physical origin is not at all clear. In this communication we show that the Hubbard model with occupation-dependent hopping (t1 - t3 - U model), recently proposed to account for the relaxation of doubly-occupied orbitals, reduces, in a physically relevant parameter region, to an effective t - J - t′ model with no upper bound on the J/t ratio. Results of exact diagonalization studies on finite size systems demonstrate the equivalence between the t1 - t2 - t3 - U model with intermediate/large U and the t - J - t′ even for very large J/t ratio (up to 16). On the contrary, t - U and t - J models turn out to be equivalent to t - J - t′ model only for very small J values (J much smaller than t). Implications of the results on high-TC superconductivity are briefly discusses.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11381/2430042
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 3
  • ???jsp.display-item.citation.isi??? 3
social impact