1995/08/16 by Elbio Dagotto, E. Dagotto, J. Riera +4 · 2 citations
Materials Science · Physics and Astronomy · #Advanced Condensed Matter Physics #Magnetic and transport properties of perovskites and related materials #Physics of Superconductivity and Magnetism #cond-mat
paper · pdf · doi:10.1103/physrevlett.76.1731
REVTex, 3 figures available upon request
arxiv created 1995/08/16 · openalex publication_date 1996/03/04 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We propose an electronic model for the recently discovered hole doped compound Y_2\ensuremath-xCaxBaNiO5. From a multiband Hamiltonian with oxygen and nickel orbitals, a one band model is discussed. Holes are described using Zhang-Rice-like S\phantom\rule0ex0ex=\phantom\rule0ex0ex(1)/(2) states at the nickels propagating on a S\phantom\rule0ex0ex=\phantom\rule0ex0ex1 spin chain. Using numerical techniques to calculate the dynamical spin structure factor S(q,\ensuremathω) in a realistic regime of couplings, spectral weight in the Haldane gap is observed in agreement with neutron scattering data. The case of static defects relevant for Zn-doped chains is also discussed. Ferromagnetic states at high hole mobility are favored in our model, contrary to what occurs in the 1D t-J model.