Thermoelectric power of cerium and ytterbium intermetallics

The temperature dependence of the thermoelectric power (TEP) of metallic systems with cerium and ytterbium ions exhibits characteristic features which we explain by the Coqblin-Schrieffer model (CSM). We specify a given system by the degeneracy and splitting of the crystal-field (CF) levels, the strength of the exchange and potential scattering, and the number of f electrons or f holes; for cerium and ytterbium ions we assume n(f)less than or equal to1 and n(f)(hole)less than or equal to1, respectively. The Kondo temperature T-K is then generated by the poor man's scaling; it separates a local-moment (LM) from a Fermi-liquid (FL) regime. In the LM regime (Tgreater than or equal toT(K)) we calculate the TEP by a renormalized perturbation expansion, in which the exchange coupling J is also renormalized by the poor man's scaling. This gives the TEP with a large peak at high temperatures and a sign change at T(x)similar or equal toalphaT(K), where for parameters used in this paper we have alpha between roughly 2.5 and 10. For n(f)similar or equal to1 and large CF splitting, we find a broad temperature range T-K