The surface phase diagram of Fe₃O₄(001) revisited

Author(s)

Panukorn Sombut, Matthias Meier, Moritz Eder, Thomas Angerler, Oscar Gamba, Michael Schmid, Ulrike Diebold, Cesare Franchini, Gareth S. Parkinson

Abstract

Understanding how the physical and electronic structures of metal-oxide surfaces evolve under varying conditions is crucial for optimizing their performance in applications such as catalysis. In this study, we compute the surface phase diagram of the Fe3O4(001) facet using density functional theory (DFT)-based calculations, with an emphasis on understanding the terminations observed in surface science experiments. Our results reveal two stable terminations in addition to the subsurface cation vacancy (SCV) structure, which dominates under oxidizing conditions. The commonly reported octahedral Fe pair, also known as the Fe-dimer termination, is stable within an oxygen chemical potential range of −3.1 eV < μO < −2.3 eV. We identify the lowest-energy structure of this surface as the one proposed by J. R. Rustad, E. Wasserman and A. R. Felmy, A Molecular Dynamics Investigation of Surface Reconstruction on Magnetite (001), Surf. Sci., 1999, 432, 1-2, where a tetrahedrally coordinated FeA atom is replaced by two octahedrally coordinated FeB atoms in the surface layer. This transformation serves as a precursor to the emergence of an FeO-like termination under highly reducing conditions. A key insight from our study is the importance of thoroughly sampling different charge-order configurations to identify the global minima across varying stoichiometries.

Organisation(s)

Computational Materials Physics

External organisation(s)

Technische Universität Wien, Université de Lorraine, University of Bologna

Journal

RSC Applied Interfaces

No. of pages

11

ISSN

2755-3701

DOI

https://doi.org/10.1039/d5lf00022j

Publication date

03-2025

Peer reviewed

Yes

Austrian Fields of Science 2012

103018 Materials physics, 103043 Computational physics, 103020 Surface physics

ASJC Scopus subject areas

Materials Science (miscellaneous), Ceramics and Composites, Materials Chemistry, Surfaces, Coatings and Films

Portal url

https://ucrisportal.univie.ac.at/en/publications/c4918fc7-43d9-4d07-82fe-c65edb74f1cd