Using ab initio thermodynamics we compile a phase diagram for the surface of Fe3O4(001) as a function of temperature and oxygen pressures. A hitherto ignored polar termination with octahedral iron and oxygen forming a wave-like structure along the [110]-direction is identified as the lowest energy configuration over a broad range of oxygen gas-phase conditions. This novel geometry is confirmed in a x-ray diffraction analysis. The stabilization of the Fe3O4(001)-surface goes together with dramatic changes in the electronic and magnetic properties, e.g., a halfmetal-to-metal transition.
@article{arxiv.cond-mat/0501402,
title = {Jahn-Teller stabilization of a "polar" metal oxide surface: Fe3O4(001)},
author = {R. Pentcheva and F. Wendler and H. L. Meyerheim and W. Moritz and N. Jedrecy and M. Scheffler},
journal= {arXiv preprint arXiv:cond-mat/0501402},
year = {2009}
}