Theoretical study on the electronic structures and optical properties of crystal with interstitial oxygen atom

The electronic structures and absorption spectra for Y AlO 3 (YAP) crystal with and without interstitial atom ( O i ) are studied using the CASTEP code with lattice structure optimized. The calculated absorption spectra of YAP containing O i ( Y AP : O i ) exhibit new absorption bands in the region from 190 to 250 nm compared with that of perfect YAP crystal. The absorption bands of YAP crystal show anisotropy and its optical symmetry coincides with the lattice structure geometry of the YAP crystal. By analyzing the calculated results it can be concluded that the O i in YAP cause significant lattice distortion around it and is responsible for the new appeared absorption bands from 190 to 250 nm.