Oxide-oxide interfaces: Atomistic and density functional study of cubic-ZrO2(100)vertical bar vertical bar NiO(111)

The cubic-ZrO2 (100) parallel to NiO (111) interface provides an opportunit y for comparison between atomic-scale measurements, atomistic simulations, and theoretical electronic structures. High-resolution electron microscopy indicates that the oxides share a common oxygen layer and that the small la ttice strain is largely taken up by NiO near the interface. Using simple Co ulomb plus Buckingham-type interatomic potentials, we are able to provide a more focused picture, revealing two types of boundary. The lowest energy i nterface is highly planar, almost ideal in structure; there is a second int erface, of higher energy, that shows a rumpled structure with strain taken up by deformation of nickel chains. Depth profiling of atomic site energies permits calculation of interface versus bulk and surface energies, and it shows that the interface effects penetrate only two to three atomic layers. Embedded cluster density functional studies of bulk and interface-region s ites permit the characterization of perturbations of electronic density aro und the boundaries.