Photoemission theory for nonlocal potentials: application to Ni(100)

A one-step theory of photoemission for nonlocal potentials which overcomes different limitations of the original theory has been applied to Ni(100). The theory is formulated for one-particle potentials and general nonlocal, complex and energy-dependent self-energies. It applies to semi-infinite lattices with perfect lateral translational invariance and arbitrary number of atoms per unit cell. In the framework of this theory the final state is calculated using multiple scattering techniques. The initial state, which is described by the energy- and temperature dependent spectral function, results from a combination of a one-particle slab calculation with many-body techniques. Here we present temperature-dependent photoemission intensities calculated for different excitation energies from the (100)-surface of ferromagnetic Ni.