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

The density fluctuation spectrum $N(\mathbf{k},\omega )$ is calculated for the t-J model in the low-doping regime using a slave-fermion method for the constrained fermions. The obtained res…