Anisotropic transport properties of cerium Kondo compounds

The anisotropy of transport properties, i.e., the electrical resistivity, the thermoelectric power, and the thermal conductivity, observed experimentally in single crystals of noncubic cerium Kondo compounds, is studied here theoretically in a model that takes into account both crystal-field and Kondo effects. At temperatures that are high compared with the Kondo temperature, we use perturbation theory on the Coqblin-Schrieffer Hamiltonian, and at low temperatures we use the slave-boson technique on the periodic Anderson Hamiltonian. We study also the effect of disorder and the resulting relation between the residual resistivity and the coefficient of the resistivity ${\mathit{T}}^2$ law. Detailed comparison with experiment is finally given and a reasonable agreement is obtained for cerium Kondo compounds, such as ${\mathrm{CePt}}_2$ ${\mathrm{Si}}_2$, ${\mathrm{CeCu}}_6$, or ${\mathrm{CeAl}}_3$.