Block-Layer Concept for the Layered Co Oxide: A Design for Thermoelectric Oxides

High-Tc Cu oxides consist of the alternating stack of the superconductive CuO2 layer and the block layer, such as Bi2Sr2O4 or La2-xSrxO2. By changing the block layer, we can change their physical properties, such as transition temperature Tc. The thermoelectric Co oxides have a similar layered structure composed of the conductive CoO2 layer and the blocking layer. Thus, we propose that their thremoelectric properties can be finely tuned by modifying the block layer.