Electronic structure and thermoelectric properties of CuRh1-xMgxO2

Electronic structure calculations using the augmented spherical wave method have been performed for CuRhO2. For this semiconductor crystallizing in the delafossite structure, it is found that the valence-band maximum is mainly due to the 4d t(2g) orbitals of Rh3+. The structural characterizations of CuRh1-xMgxO2 show a broad range of Mg2+ substitution for Rh3+ in this series, up to about 12%. Measurements of the resistivity and thermopower of the doped systems show a Fermi-liquidlike behavior for temperatures up to about 1000 K, resulting in a large weakly temperature-dependent power factor. The thermopower is discussed both within the Boltzmann equation approach as based on the electronic structure calculations and the temperature-independent correlation functions ratio approximation as based on the Kubo formalism.