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O: Fachverband Oberflächenphysik

O 20: Oxides II: Structures, Interactions and Reducibility

O 20.8: Vortrag

Montag, 16. März 2020, 17:30–17:45, WIL B321

Ab-initio studies of the (110) surface terminations of rutile VO2 — •Jakub Planer, Florian Mittendorfer, and Josef Redinger — Vienna University of Technology, 1040 Vienna, Austria

Vanadium dioxide is a promising candidate for fast electronic or optical switching. These applications are based on an insulator-to-metal transition which occurs at 340 K and is accompanied by the structural change from a monoclinic to a rutile phase.

Despite the potential usability of the VO2, many open questions remain with respect to its surface structure. We will therefore discuss properties of the rutile VO2 (110) surface under varying oxygen partial pressure, and compare our results to recent experimental findings. Although standard GGA functionals (PBE) offer an appropriate description of the structural properties of the rutile and monoclinic phase, the surface properties such as surface energy or stability of surface reconstructions are not captured well. Advanced functionals such as meta-GGA approaches (SCAN) implemented in the Vienna Ab initio Simulations Package (VASP) thus have been employed to overcome these shortcomings.

It is experimentally found that the VO2 surfaces contain more oxygen than the bulk. This is in agreement with the previous study focused on the oxygen adsorption on the (110) surface. However, our work shows different oxygen-rich tetrahedral surface terminations that are related to the vanadium pentoxide (001) monolayer, in agreement with the STM results.