An extended Gutzwiller Ansatz which incorporates the correlation between nearest neighbour empty and doubly occupied sites, is used to describe the ground state of the half-filled 1d hubbard model in the limit t/U<<1. Application of the single-site Gutzwiller approximation allows a fully analytic treatment, and the ground state energy is found to have the correct asymptotic form-t2U. An analytically tractable simple improvement of the Gutzwiller approximation is suggested, which allows to describe near-neighbour spin and charge correlations, both in half-filled and nearly half-filled cases. Consequences for the renormalization factor q are also discussed.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering