Ab initio Calculations of Bulk and (001) Surface F-centers in ABO3 Perovskites

Abstract

We analyzed systematic trends in BaTiO3, SrTiO3, PbZrO3 and SrZrO3 bulk as well as very rarely performed (001) surface F-center ab initio calculations. The nearest neighbor atomic displacements around the bulk F-center in the ABO3 perovskites are considerably smaller than the relevant neighbor atomic displacements around the (001) surface $F$-centers. The $F$-center electrons are more delocalized for the ABO3 perovskite (001) surface $F$-center than for the bulk $F$-center. Our calculated formation energy differences between the BaTiO3, SrTiO3, PbZrO3 and SrZrO3 bulk and its (001) surface $F$-centers triggers the $F$-center segregation from the bulk crystal towards the ABO3 perovskite (001) surface.