ARPES photointensities from cuprates: Matrix element effects, energy and
site selectivities, role of the third dimension, and related issues

Seppo Sahrakorpi

Physics Department, Northeastern University, 110 Forsyth Street, Boston, MA 02115, USA

S. Sahrakorpia, Hsin Lina, V. Arpiainenb, M. Lindroosa,b, R.S. Markiewicza and A. Bansila a. Physics Department, Northeastern University, Boston, Massachusetts, USA b. Institute of Physics, Tampere University of Technology, Tampere, Finland Selected results from our recent angle-resolved photoemission (ARPES) first principles computations in cuprates are presented. We focus on results concerning the selectivity properties of the ARPES matrix element in optimally doped La2-xSrxCuO4 (LSCO, x=0.15) with respect to contributions from specific atomic sites and/or orbitals in the system. We find that for photon energies up to 70 eV, the ARPES intensity is dominated by contributions from oxygen p- and copper s- and d-orbitals. The present results combined with our previous analysis[1,2,3] of Bi2Sr2CaCu2O8 (Bi2212), indicate that site- and orbital-selectivity effects hold more generally in ARPES from cuprates. We comment on the role of the third dimension on the ARPES spectra of Bi2212 and LSCO and how the kz dispersion in the cuprates induces an irreducible width to spectral lines, which is not connected with a scattering mechanism[4,5]. These and other computations, some within the framework of the tight binding models, are used to gain insight into issues of current interest in the cuprate physics. [1.] M. Lindroos, S. Sahrakorpi, and A. Bansil, PRB 65, (2002) 054514. [2.] S. Sahrakorpi, M. Lindroos, and A. Bansil, PRB 68, (2003) 054522. [3.] A. Bansil, R.S. Markiewicz, C. Kusko, M. Lindroos, and S. Sahrakorpi, J. Phys. Chem. Solids 65, (2004) 1417. [4.] A. Bansil, M. Lindroos, S. Sahrakorpi, and R.S. Markiewicz, PRB Brief Report (2004). [5.] S. Sahrakorpi, M. Lindroos, R.S. Markiewicz, and A. Bansil, (unpublished).