Electronic structure and transport of Ca3Co2O6 and Ca3CoNiO6

We have calculated the band structure of Ca3Co2O6 and Ca3CoNiO6 by using the self-consistent full-potential linearized augmented plane-wave method within density function theory and the generalized gradient approximation for the exchange and correlation potential. The spin–orbit interaction is incorporated in the calculations using a second variational procedure. The relation of these band structure calculations to thermoelectric transport is discussed. The results illustrate that transport is highly anisotropic with much larger mobility in the a–b plane than out of the a–b plane, and the introduction of Ni in Ca3Co2O6 alters its electronic structure and its thermoelectric transport properties.