We show that the exact ground state for a class of extended Hubbard models including bond-charge, exchange, and pair-hopping terms, is the Yang ''eta-paired'' state for any nonvanishing positive value of the pair-hopping amplitude, at least when the on-site Coulomb interaction is attractive enough and the remaining physical parameters satisfy a single constraint. The ground state is thus rigorously superconducting. Our result holds on a bipartite lattice in any dimension, at any band filling, and for arbitrary electron hopping.
|Titolo:||Rigorous results on superconducting ground state of attractive extended Hubbard models|
|Data di pubblicazione:||1996|
|Appare nelle tipologie:||1.1 Articolo in rivista|