First principles computation of dynamical structure factor in real and momentum space in cuprates

We present a method for efficient, accurate first-principles calculations of the dynamical structure factor $S(\textbf{q},\omega)$ in periodic systems, using products of real space Green functions and fast Fourier transforms (FFT). We further invert $S(\textbf{q},\omega)$ via Fourier transformation [1] to reconstruct the propagator of electron density $X(\textbf{x},t)$ in real space and time domain, thereby visualising spatially the dynamics of an electron doped cuprate system in real time. The present method is useful for many-body perturbation theories of excitations based on Density Function Theory (DFT) and modeling of various highly resolved spectroscopies going beyond the standard LDA [2-5]. Some illustrative examples will be presented. Work supported by the US DOE.\\[4pt] [1] P. Abbamonte \textit{et al.}, Phys. Rev. Lett. {\bf 92}, 237401 (2004).\\[0pt] [2] Susmita Basak \textit{et al.}, Phys. Rev. B {\bf 80}, 214520 (2009).\\[0pt] [3] J. Nieminen \textit{et al.}, Phys. Rev. B {\bf 80}, 134509 (2009). \\[0pt] [4] R. S. Markiewicz \textit{et al.}, Phys. Rev. B {\bf 77}, 094518 (2008).\\[0pt] [5] G. Stutz \textit{et al.}, Phys. Rev. B {\bf 60}, 7099 (1999).