RELATIVISTIC PHOTOEMISSION THEORY APPLIED TO GAAS(110)

A fully dynamical one-step theory of photoemission for several atoms per unit cell is presented. The theory is a relativistic generalization of the original work due to Pendry and allows us to calculate photoemission and bremsstrahlung isochromat spectra for pure elemental solids and compounds. The key aspect of the model consists of the formulation of the dipole matrix elements in the velocity form to guarantee a maximum amount of numerical stability in the computational implementation. In this contribution we apply our theory to spin-integrated and spin-resolved photoemission calculations for the GaAs(110) surface and observe an excellent agreement between theoretical results and experimental data for the spin-integrated spectra. Further good agreement is obtained for the maximum calculated degree of spin polarization and the corresponding experimental values measured in energy and angle-integrated photoemission (photoyield) experiments.