Spin Dynamics of Hole Doped ${\rm Y_{2-x} Ca_x Ba Ni O_5}$

E. Dagotto; J. Riera; A. Sandvik; A. Moreo

doi:10.1103/physrevlett.76.1731

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Spin Dynamics of Hole Doped ${\rm Y_{2-x} Ca_x Ba Ni O_5}$

E. Dagotto·J. Riera·A. Sandvik·A. Moreo

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Abstract

We propose an electronic model for the recently discovered hole doped compound ${\rm Y_{2-x} Ca_x Ba Ni O_5 }$. From a multiband Hamiltonian with oxygen and nickel orbitals, a one band model is derived. Holes are described using Zhang-Rice-like S=1/2 states at the nickels propagating on a S=1 spin chain. Using numerical techniques to calculate the dynamical spin structure factor ${\rm S(q,ω)}$ in a realistic regime of couplings, spectral weight in the Haldane gap is observed in agreement with neutron scattering data. Low energy states with S=3/2 appear in the model. Several predictions are made to test these ideas.

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E. Dagotto, J. Riera, A. Sandvik, A. Moreo. 1995-08-16. Spin Dynamics of Hole Doped ${\rm Y_{2-x} Ca_x Ba Ni O_5}$. https://doi.org/10.1103/physrevlett.76.1731

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