Fermi Liquid Description of X-ray Absorption Spectra in Overdoped LSCO

We show that a paramagnetic self-energy correction [1] to the real-space Green's function code FEFF9 [2] can provide a good description of the x-ray absorption spectra (XAS) of cuprate system such as La$_{\rm (2-x)}$Sr$_{\rm (x)}$CuO$_{\rm 4}$ (LSCO). This self energy includes coupling to both charge and magnetic excitations. We also find good agreement with recent XAS results of Peet et al. [3] in the over-doped regime of LSCO. We have also investigated various prescriptions for including core-hole effects. We infer that at low doping, the system behaves as an anti-ferromagnetic insulator, while Fermi liquid physics is recovered at high doping. \\ \mbox{[1]}Tanmoy Das, R.S. Markiewicz, and A. Bansil, Phys.Rev. B {\bf 77}, 134516 (2008). \\ \mbox{[2]} J. J. Rehr et al., Comptes Rendus Physique {\bf 10}, 548 (2009).\\ \mbox{[3]} D.C. Peets \textit{et al.}, Phys. Rev. Lett. {\bf 103}, 087402 (2009).