Composite effects in the electronic structure of Au-Pd and Ag-Pd

• Published in: Vacuum Vol. 46; no. 5; pp. 469 - 471
• Main Authors: Wronkowska, Aleksandra A, Wronkowski, Andrzej
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford Elsevier Ltd 01.05.1995; Elsevier
• Subjects: Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron states and collective excitations in multilayers, quantum wells, mesoscopic, and nanoscale systems; Electron states and collective excitations in thin films, multilayers, quantum wells, mesoscopic and nanoscale systems; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Metals and metallic alloys; Metals. Metallurgy; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of specific thin films; Physics; Thin films; Silver; Gold; Composite materials; Transition elements; Diffusion; Experimental study; Permittivity; Substrates; Ellipsometry
• ISSN: 0042-207X; 1879-2715
• DOI: 10.1016/0042-207X(94)00108-1

The understanding of the electronic structure of disordered alloys and bimetallic systems is not yet as advanced as that of ordered crystals. Spectroscopic optical conductivity measurements provide the most direct method for determining the electronic properties of the disordered systems and impurity states. In this paper we present preliminary studies of changes in the electronic structure of host metals during diffusion of Pd atoms through thin films of Au and Ag. The samples were prepared by evaporation of about 200 nm thick films of Au and Ag onto pure Pd foils. The influence of transition metal atoms, located in the grain boundaries and inside of noble metal grains, on the optical properties of the systems has been investigated by means of spectroscopic ellipsometry, in the photon energy range 1.65–3.1 eV. The experimental results are qualitatively interpreted on the basis of an effective medium composite microstructure and the virtual-bound-state model, which applies to the diluted transition-noble-metal alloys.