Abstract
The geometries and electronic structures of have been investigated using density-functional theory with on-site corrections for strongly correlated systems for . Al is found to be well described within the ionic model, with a valence charge corresponding to a oxidation state. Substituting Cr for Al is predicted to increase the density of states at the top of the valence band, in agreement with experimental x-ray photoemission spectroscopy data. Analysis of atom-projected densities of states and valence charges suggests that this is due to increased covalency between Cr and O; the valence charge for O in the Cu-O-(Al,Cr) subunits changes from to when Cr replaces Al. This produces an indirect oxygen-mediated change to the states.
2 More- Received 18 September 2008
DOI:https://doi.org/10.1103/PhysRevB.79.035101
©2009 American Physical Society