Abstract
The geometries and electronic structures of CuAl1−xCrxO2 have been investigated using density-functional theory with on-site corrections for strongly correlated systems (GGA+U) for x=0,1/2,1. Al is found to be well described within the ionic model, with a valence charge corresponding to a +3 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 −1.74 to ∼−1.25 when Cr replaces Al. This produces an indirect oxygen-mediated change to the Cu d states.
Original language | English |
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Article number | 035101 |
Journal | Physical Review B |
Volume | 79 |
Issue number | 3 |
DOIs | |
Publication status | Published - 5 Jan 2009 |
Keywords
- aluminium compounds
- valence bands
- correlated electron systems
- oxidation
- electronic density of states
- theory
- cugao2
- cualo2
- density functional
- doping
- semiconductor
- crystal-structure
- conductivity
- 1st-principles
- oxide
- thin-films
- copper compounds
- transparent
- X-ray photoelectron spectra
- chromium
- strongly
- gradient