We present angle-resolved photoemission (normal-emission) measurements from the (100) surface of a disordered ${\mathrm{Au}}_{70}$${\mathrm{Pd}}_{30}$ alloy single crystal using He i, Ne i, He ii, and Ne ii excitations. The experimental results are interpreted via fully relativistic Korringa-Kohn-Rostoker coherent-potential-approximation computations of complex-energy bands, spectral densities, and total and site-decomposed densities of states in the alloy. Our measurements and calculations indicate that the main effects of adding Pd to Au are the following: (i) the appearance of a Pd-derived d-band complex with small dispersion, distinctly above the Au d-band edge, centered about 1 eV below the Fermi energy, (ii) the Au-derived d-band complex in the alloy is approximately 5 eV wide and is split by spin-orbit interaction into two peaks 2.1 eV apart, and (iii) levels of d symmetry generally suffer much larger disorder-induced smearings compared with those for levels possessing s-p symmetry.

• Received 6 March 1990

DOI:https://doi.org/10.1103/PhysRevB.42.8820