Regensburg 2022 – wissenschaftliches Programm
O 23.4: Poster
Montag, 5. September 2022, 18:00–20:00, P4
Structure of NbO Nanocrystals on the Nb(110) Surface — •Samuel Berman1, Kuanysh Zhussupbekov1, Ainur Zhussupbekova1, Brian Walls1, Killian Walshe1, Sergey I. Bozhko1,2, Andrey Ionov2, David D. O'Regan1,3, and Igor V. Shvets1 — 1School of Physics and Centre for Research on Adaptive Nanostructures and Nanodevices (CRANN), Trinity College Dublin, Dublin 2, Ireland — 2Chernogolovka — 3AMBER, the SFI Research Centre for Advanced Materials and BioEngineering Research, Dublin 2, Ireland
The properties of Niobium based devices are greatly influenced by the presence of surface oxygen. The highly stable NbO(111) overlayer on the Nb(110) surface is known to host a distinctive nanocrystal structure, as observed by scanning tunnelling microscopy. However the exact structure of this surface has remained a mystery. In order to understand this surface structure, we carry out density functional theory calculations, along with scanning tunnelling microscopy/spectroscopy and X-ray/ultraviolet photoelectron spectroscopy experiments. We propose a new model, contrary to those previously proposed in the literature. The nanocrystal pattern is ascribed to a subtle reconstruction in the surface layer which locally breaks the hexagonal NbO(111) symmetry, giving rise to modulations in the local density of states. Excellent agreement is found between our model and the observed experimental data. We also investigate the underlying reasons that the surface adopts this unusual structure.