Density response of the t-J model and renormalization of breathing and half-breathing phonon modes: A slave-fermion calculation

P. Horsch; G. Khaliullin; V. Oudovenko

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Density response of the t-J model and renormalization of breathing and half-breathing phonon modes: A slave-fermion calculation

P. Horsch·G. Khaliullin·V. Oudovenko

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Abstract

The density fluctuation spectrum $N({\bf k},ω)$ is calculated for the t-J model in the low-doping regime using a slave-fermion method for the constrained fermions. The obtained results for $N({\bf k},ω)$ are in good agreement with diagonalization results. The density response is characterized by incoherent, momentum dependent spectral functions reaching up to energies $\sim 8t$ and a low-energy structure at energy $\sim J$ due to transitions in the quasiparticle band. $N({\bf k},ω)$ is shown to lead to a strong renormalization of planar bond-streching and breathing phonon modes with a large phonon linewidth at intermediate momenta caused by the low-energy response. Our results are consistent with recent neutron scattering data, showing the peculiar behavior of these modes.

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P. Horsch, G. Khaliullin, V. Oudovenko. 2001-08-17. Density response of the t-J model and renormalization of breathing and half-breathing phonon modes: A slave-fermion calculation. https://arxiv.org/abs/cond-mat/0108279

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