Concentration of Vacancies at Metal-Oxide Surfaces: Case Study of MgO

Fig. S1 shows the cluster models that were employed for the DFT calculations of formation energies for defects at different configurational sites of the MgO (100) surface and in MgO bulk. All the clusters are embedded in a periodic array of point charges at the optimized PBE (pbc) cell parameter. For the surface models the positions of the point charges coincide with the coordinates of a relaxed defect-free 5-layer slab. The CCSD(T) computations for the neutral oxygen vacancy in the bulk and at the MgO (100) terrace were performed using the embedded cluster models shown in Fig. S2. While all other embedded cluster calculations were performed with TURBOMOLE, this bulk model was also used for FHI-aims calculations at DFT level and for method validation employing G0W0@HSE.