Atomic structure and composition of the yttria-stabilized zirconia (111) surface

► Anomalous surface X-ray diffraction was used to investigate the YSZ(111) surface. ► The surface morphology exhibits a high number of small islands. ► After annealing in UHV the morphology persists and Y-segregation is observed. ► After annealing in UHV zirconium and oxygen vacancies are observed. ► The uncovered site occupancies and vacancies are important as reactive centers.