Site and orbital selectivity properties of angle-resolved photoemission from the cuprates

Abstract

We discuss how different sites and orbitals contribute to the ARPES spectra of the cuprates by considering the nature of the dipole matrix element involved in the underlying photoexcitation process. Results on La2−xSrxCuO4 (LSCO) are presented over the photon energy range of 5–60 eV for k‖ values covering the entire Fermi surface (FS). The computed spectra are found to be sensitive to not only the Cudx2−y2 and O px/py orbitals in the CuO2 planes, but also to the c-axis oriented Cudz2 and apical O pz orbitals, which are usually ignored in modeling the electronic structure of the cuprates. In the low photon energy range of 5–25 eV, the spectra are dominated by contributions of the O px/py orbitals. Results on LSCO are compared with those on Bi2Sr2CaCu2O8 (Bi2212) for 5–25 eV photons as a way of obtaining insight into the similarities and differences in the response of the CuO2 planes to the photoexcitation process in different cuprates.