Using scanning tunneling microscopy, low-energy ion scattering and quantitative low-energy electron diffraction, we find about 17% metal vacancies on the oxygen-covered Cr(100) surface. The oxygen atoms occupy all hollow sites of the first layer, including those neighboring a Cr vacancy. We argue that the vacancy formation is energetically favoured and not caused by stress but rather by electronic effects.
Corresponding author: M. Schmid (schmid)
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