Electronic structure of NbxMo100-x solid solutions

NbxMo100-x solid solutions (0 less than or equal to x less than or equal to 100) have been studied by means of photoelectron spectroscopy in order to obtain direct information concerning the electronic density of states of the alloy. Detailed knowledge of the density of states is relevant to the discussion of electronic properties such as the superconducting transition temperature. Changes observed in the valence-band spectra as a function of systematic changes in x follow a very simple law proposed in the early days of solid-state physics known as the rigid-band model (RBM). The observed binding energy shifts of the ''rigid'' valence band on alloying agree fairly well with predictions based on modern band-structure calculations for the pure components, verifying that this simple model can be used even quantitatively as has been assumed in the past. The dependence of the superconducting transition temperature on the concentration can be very well understood on the basis of this RBM description of the electronic structure.