Thermoelectric power in CeT4M (T=Cu, Ni; M=In, Ga) compounds

CeCu4In and CeCu4Ga compounds belong to heavy fermion (HF) systems. CeNi4In and CeNi4Ga seems to be on the border between HF and mixed-valence (MV) states. It has been observed that thermoelectric power (TEP) shows a significant difference between these Cu and Ni-based compounds, whereas thermal conductivity does not reveal such dramatic changes in the temperature dependencies. These results are analyzed assuming the Kondo effect at presence of the crystal electric field for the HF compounds and two density of states peaks in the region of the Fermi level for the remaining compounds. The details of the electronic structure are supposed to be responsible for the negative TEP of CeNi4M.