Parametrized scheme for calculating angle-resolved photoemission spectra from the fccd-band metals

Abstract

A parametrized scheme is developed for calculating angle-resolved photoemission spectra from the valence bands of the fcc $d$-band metals. We take as a starting point the result for the photo-current in a one-step model when final-state damping and dielectric screening of the free-space electric field are neglected. With use of scattering theory, a model for the final-state wave function ${\ensuremath{\psi}}^{f}$ near the surface is derived, in which ${\ensuremath{\psi}}^{f}$ is written as a linear combination of orthogonalized plane waves with group velocities directed both into and out of the bulk. This result is then generalized to obtain a model for ${\ensuremath{\psi}}^{f}$ in the presence of electron damping, and a parametrized, $z$-independent, model for the screened electric field within the solid is adopted. Initial-state energies and wave functions are obtained using a combined interpolation scheme. Optical transition matrix elements are evaluated by adopting parametrized expressions for integrals involving the radial wave functions for the various angular momentum components of the initial and final states within a muffin-tin sphere. The use of this scheme as an improved method for extracting initial-state band positions from experimental photoemission spectra is discussed.