A Tight Binding Approach to Understanding the Orbital Character of Pb-BSSCO and its Effects on Photoemission Matrix Elements*

We measure the near Fermi energy electronic structure of Pb-BSCCO using Angle Resolved Photoemission Spectroscopy (ARPES) for various light polarization, incident at a glancing angle. A strong dependence of the photocurrent for a given crystal momentum on the polarization of light is observed. A minimal model tight binding calculation in a basis of local atomic orbitals is then utilized to determine the orbital composition of the single particle wavefunction as a function of crystal momentum in a single CuO2 plane. Building off of these results, we simulate the relative ARPES photocurrent throughout crystal momentum space in the dipole approximation and compare to our experimental data. These comparisons confirm the presence of changing wavefunction orbital composition throughout the Brillouin zone in Pb-BSCCO.