On rigid bands and mass enhancements in noble metal alloys

The rigid band model assumes that the electronic density of states of an alloy can be inferred from that of the host. Band calculations are usually inconsistent with this model when compared with the measured electronic specific heat of alloys. It has been suggested that the apparent discrepancy for alloys with noble metal hosts is due to the neglect of changes in the electron-phonon enhancement of the density of states at the Fermi level. A semi-empirical calculation, based on measurements of the high temperature electrical resistivity, shows that changes in the enhancement factor are much too small to account for the failure of the rigid band model.