Figure 1

Magnetite [111] vacuum slab (a) (side view) and oxygen termination on top of Fe-octahedral layer (b) (top view).Reuse & Permissions

Figure 2

STM images $10.5\times 8.5{\mathrm{n}\mathrm{m}}^2$, $7\times 8{\mathrm{n}\mathrm{m}}^2$, and $12.0\times 17.5{\mathrm{n}\mathrm{m}}^2$) of the superstructure without (a) and with magnetic field (b),(c). Circles mark the oxygen vacancies in the topmost surface layer. (b) Three bright spots appear around vacancy that correspond to Fe sites with 6 Å interatomic distance; (c) a case of higher density of defects. Multiple vacancies are now surrounded by the number of bright spots, which still has the same periodicity and symmetry as in (b). ($V_{\mathrm{b}\mathrm{i}\mathrm{a}\mathrm{s}}=-1.0\mathrm{V}$, $I_t=0.1\mathrm{n}\mathrm{A}$, MnNi tip). Insets show a high-resolution image of the defects. (d) Schematic representative of the STM line profile (solid curve, magnetic field applied; dashed line, no magnetic field) above an oxygen defect. [Oxygen atoms are white circles, and Fe atoms, gray; tip position 2 indicates the magnetic contrast maxima seen in Fig. 2b].Reuse & Permissions

Figure 3

(a) Partial density of states corresponding to (top) $2p$ (O) states in close-packed oxygen topmost layer; (middle) $3d$ (Fe) states in the Fe-octahedral layer, next to the topmost oxygen layer; (bottom) $2p$ (O) states in the third layer. Spin-up electron density above the oxygen-terminated surface: ideal surface layer (b), and in the presence of an oxygen vacancy (c). The sketch of energy range [$E_F-1\mathrm{e}\mathrm{V},E_F$] was chosen to make it comparable with STM data ($V_{\mathrm{b}\mathrm{i}\mathrm{a}\mathrm{s}}=-1\mathrm{V}$). The $(2\times 2)$ supercell used in the calculations is marked.Reuse & Permissions