Electronic Structure and Bonding in CuMO2(M = Al, Ga, Y) Delafossite-Type Oxides: An Ab Initio Study

The structural and electronic properties of some simple ternary oxides with the delafossite-type structure have been investigated using the periodic Hartree−Fock method and a posteriori density-functional corrections. The coexistence in the same crystal structure of different structural motifs, such as MO 6 octahedra, linear O−Cu−O units, and hexagonal Cu layers with relatively short Cu−Cu distances, enables accurate calculation of the structural data for this type of material rather difficult: correlation effects seem only to be important for the description of the Cu−O bonds, while the geometry of the MO 6 octahedra is best described by the Hartree−Fock method. The analysis of bonding in the Cu layers reveals the existence of weak d 10 −d 10 interactions that are suggested to be important in the determination of the electrooptical properties of doped delafossites.