Spectral evidence for the importance of single-site effects in heavy-fermion uranium materials

Abstract

The 5f spectral weights in the heavy-fermion alloy system ${\mathrm{U}}_{\mathrm{x}}$${\mathrm{Y}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Al}}_{2}$ (x=0.1,0.02) have been measured by resonant photoemission. The major features of the spectra of the dilute systems are identical to those for x=1, showing that single-site effects dominate the large--energy-scale features of the spectrum even in the concentrated system.