Experimental techniques and density-functional theory have been employed to identify the surface composition and structure of SnO2(101). The stoichiometric Sn4+O22- surface is only stable at high oxygen chemical potential. For lower oxidizing potential of the gas phase a Sn2+O2- bulk termination is favored. These two surfaces convert into each other without reconstruction by occupying and vacating bridging oxygen sites. This variability of the surface composition is possible because of the dual valency of Sn and may be one of the fundamental mechanisms responsible for the performance of this material in gas-sensing devices.
Corresponding author: U. Diebold (diebold).
Users with online access to Europhysics Letters (EPL) can load the article from the publisher.