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Theory of the thermoelectricity of intermetallic compounds with Ce or Yb ions

The thermoelectric properties of intermetallic compounds with Ce or Yb ions are explained by the single-impurity Anderson model which takes into account the crystal-field splitting of the 4f ground-state multiplet, and assumes a strong Coulomb repulsion which restricts the number of f electrons or f holes to nf1 for Ce and n1 for Yb ions. Using the noncrossing approximation and imposing the charge neutrality constraint on the local scattering problem at each temperature and pressure, the excitation spectrum and the transport coefficients of the model are obtained. The thermopower calculated in such a way exhibits all the characteristic features observed in Ce and Yb intermetallics. Calculating the effect of pressure on various characteristic energy scales of the model, we obtain the (T, p) phase diagram which agrees with the experimental data on CeRu2Si2, CeCu2Si2, CePd2Si2, and similar compounds. The evolution of the thermopower and the electrical resistance as a function of temperature, pressure or doping is explained in terms of the crossovers between various fixed points of the model and the redistribution of the single-particle spectral weight within the Fermi window.

Theory of the thermoelectricity; intermetallic compounds; Ce ions; Yb ions

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