Electronic structure and small polaron hole transport of copper aluminate

High-temperature electrical property measurements (electrical conductivity, thermoelectric coefficient) on polycrystalline CuAlO₂ exhibited characteristic small polaron features, i.e., low mobilities (0.1--0.4 cm²/V s) and an activation energy of {~}0.14 eV. The thermopower was p type ({~}440 {μ}V/K) and roughly temperature independent. The local-density full-potential linearized augmented-plane-wave method was used to calculate the band structure, densities of states, and optical properties (within the electric-dipole approximation) in order to account for the unique electronic and optical properties of this potential transparent conducting oxide.