Anomalous thermopower in heavy-fermion compounds CeB6, CeAl3, and CeCu6-xAux

High-precision measurements of thermopower have been performed in a wide temperature range (2-300 K) for a series of cerium-based heavy-fermion compounds, including CeB6, CeAl3, CeCu6, and substitutional solid solutions of the CeCu6 - x Au (x) system (x = 0.1, 0.2). All compounds exhibit an unusual (logarithmic) asymptotic behavior of the temperature dependence of the Seebeck coefficient: S alpha -lnT. In the case of cerium hexaboride, this anomalous behavior of S(T) is accompanied by the appearance of weak-carrier-localization-mode asymptotics in the conductivity (sigma(T) alpha T-0.39), while the paramagnetic susceptibility chi(T) and the effective mass of charge carriers m(eff)(T) vary according to a power law (chi(T), m(eff)(T) alpha T-0.8) in the temperature interval T = 10-80 K. This behavior corresponds to renormalization of the density of states at the Fermi level. The observed anomalous behavior of thermopower in CeB6 and other cerium-based intermetallic compounds is attributed to the formation of heavy fermions (many-body states in the metal matrix) at low temperatures.