Ab-initio study of oxygen vacancy stability in bulk and Cerium-doped lutetium oxyorthosilicate

Abstract We study from first principles the stability of neutral and charged oxygen vacancies in lutetium oxyorthosilicate, Lu 2 SiO 5 , as well as its possible modification due to the presence of Ce 3 + , as present in commercial scintillators. We show that the neutral oxygen vacancy with the lowest formation energy forms at the oxygen sites within the [SiO 4 ] tetrahedra instead of the interstitial oxygen site bonded exclusively to lutetium atoms. The discrepancy with a previous study is attributed to the quality of the pseudopotential. Support for these results is found by performing a bonding analysis of the oxygen sites, as well as oxygen vacancy calculations in the iso-structural Y 2 SiO 5 compound. In addition, we find that the incorporation of Ce 3 + ion does not affect the stability of oxygen vacancies in Lu 2 SiO 5 .