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Effective one-band electron-phonon Hamiltonian for nickel perovskites

J. Loos·H. Fehske
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Abstract

Inspired by recent experiments on the Sr-doped nickelates, $La_{2-x}Sr_xNiO_4$, we propose a minimal microscopic model capable to describe the variety of the observed quasi-static charge/lattice modulations and the resulting magnetic and electronic-transport anomalies. Analyzing the motion of low-spin (s=1/2) holes in a high-spin (S=1) background as well as their their coupling to the in-plane oxygen phonon modes, we construct a sort of generalized Holstein t-J Hamiltonian for the $NiO_2$ planes, which contains besides the rather complex ``composite-hole'' hopping part non-local spin-spin and hole-phonon interaction terms.

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J. Loos, H. Fehske. 1997-02-05. Effective one-band electron-phonon Hamiltonian for nickel perovskites. https://doi.org/10.1103/physrevb.56.3544

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