Effect of Phonon- and Electron-Electron-Induceds−dTransitions on the Thermopower of the Transition Metals

Using a two-band model for the conduction electrons of the transition metals and assuming that only the lighter carriers contribute to charge transport, the effects of phonon-induced and electron-electron interband $s-d$ transitions are investigated. Provided that the total thermopower, not including the phonon-drag contribution, is given by $S_T=\left(\frac{1}{W_T}\right)\Sigma i^{}{W}_i{S}_i$, we find that interband electron-electron scattering may manifest itself in the total thermopower at low as well as at high temperatures. At lowest temperatures (near $\frac{T}{{\Theta }_D}=0.03\mathrm{}$), depending upon the magnitudes and temperature dependences of electron-electron-and electron-phonon-scattering contributions, a well-defined extremum of the order of 1μV/°K may appear. At high temperatures the total thermopower, weighted as indicated above, may be dominated by electron-electron-scattering effects, and in that event, will exhibit a $T^2$ temperature dependence. The effect of the variation of some of the parameters and the influence of the addition of impurities are discussed and the theoretical total thermopower is compared with available experimental data.