Lindhard and RPA susceptibility computations in extended momentum space in electron doped cuprates

Abstract

We present an approximation for efficient calculation of the Lindhard susceptibility $\ddot{I}{‡}^L(q,\ddot{I}‰)$ in a periodic system through the use of simple products of real space functions and the fast Fourier transform (FFT). The method is illustrated by providing $\ddot{I}{‡}^L(q,\ddot{I}‰)$ results for the electron doped cuprate Nd${}_{2-x}$Ce${}_x$CuO${}_4$ extended over several Brillouin zones. These results are relevant for interpreting inelastic X-ray scattering spectra from cuprates.

6 pages, 6 figures, accepted in Physical Review B