Oxygen-terminated (1 × 1) reconstruction of reduced magnetite Fe₃O₄(111)

F. Kraushofer, M. Meier, Z. Jakub, J. Hütner, J. Balajka, J. Hulva, M. Schmid, C. Franchini, U. Diebold, G. S. Parkinson

Institut für Angewandte Physik, TU Wien, 1040 Wien, Austria

J. Phys. Chem. Lett. 14 (2023) 3258-3265

The (111) facet of magnetite (Fe₃O₄) has been studied extensively by experimental and theoretical methods, but controversy remains regarding the structure of its low-energy surface terminations. Using density functional theory (DFT) computations, we demonstrate three reconstructions that are more favorable than the accepted Fe_oct2 termination under reducing conditions. All three structures change the coordination of iron in the kagome Fe_oct1 layer to be tetrahedral. With atomically resolved microscopy techniques, we show that the termination that coexists with the Fe_tet1 termination consists of tetrahedral iron capped by 3-fold coordinated oxygen atoms. This structure explains the inert nature of the reduced patches.

Corresponding author: Gareth S. Parkinson (parkinson).

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