Angle-resolved photoemission spectra calculations in nonmagnetic alloys

The relativistic theory of angle-resolved photoemission; from nonmagnetic metal surfaces is reviewed. The problems arising from the application of existing theories to multicomponent systems are analyzed, in order to find out which information about the electronic structure can be univocally extracted from a detailed comparison between experiments and theory. In order to illustrate the theoretical points, angle-resolved photoemission spectra calculations, for the spin-polarized case, are presented for the ordered and disordered Cu3Au (1,0,0) surface. The conclusion is that, notwithstanding their drawbacks, photoemission calculations are an essential tool for understanding the experiments, and that very small details of the photoemission spectra can be related to the order-disorder transition.