Simultaneously optimizing the interdependent thermoelectric parameters in Ce(Ni1-xCux)2Al3

Substitution of Cu for Ni in the Kondo lattice system CeNi2Al3 results in a simultaneous optimization of the three interdependent thermoelectric parameters: thermoelectric power, electrical, and thermal conductivities, where the electronic change in conduction band induced by the extra electron of Cu is shown to be crucial. The obtained thermoelectric figure of merit zT amounts to 0.125 at around 100 K, comparable to the best values known for Kondo compounds. The realization of ideal thermoelectric optimization in Ce(Ni1-xCux)(2)Al-3 indicates that proper electronic tuning of Kondo compounds is a promising approach to efficient thermoelectric materials for cryogenic application.