报告人：Falko P. Netzer, Institute of Physics, Surface and Interface Physics Karl-Franzens University, Graz, AUSTRIA
Two-dimensional (2-D) transition metal oxide layers have attracted significant interest during the past decade due to their novel emergent properties and their high potential for nanotechnology applications. For practical reasons 2-D oxide layers are usually supported on metal surfaces. This leads to a coupling of the oxide overlayer to the metal substrate, often strong coupling, which creates a metal-oxide hybrid system with properties that are largely determined by the oxide-metal interface. In this talk, I will discuss the role of the metal-oxide coupling in shaping the morphology and structure of two-dimensional oxide systems. Moreover, the effects of interfacial strain on the physical and chemical properties of 2-D oxide layers will be investigated. I will discuss 3 case studies:
(1) W-oxide on Pd(100), a system with strong oxide-metal coupling, leading to a commensurate overlayer with strong strain effects;
(2) W-oxide on Ag(100), a system with weak oxide-metal coupling, leading to an incommensurate overlayer with virtually no strain;
(3) Ce-oxide on Cu(110), where the symmetry mismatch at the interface generates a spatially modulated strainfield giving rise to a periodic pattern formation.
All 2-D oxide overlayersare prepared by a PVD method and are atomically characterized experimentally in a surface science approach by STM, LEED and various electron spectrocopies, as well as theoretically by extensive DFT calculations.