Title: Metal-Supported 2-D Oxide Systems: Substrate Coupling, Commensurability and Strain Effects

Speaker:  Prof. Falko P. Netzer，Institute of Physics, Surface and Interface Physics，Karl-Franzens University, Graz, AUSTRIA

Date/Time:  3:00 PM, Nov. 1, 2018

Location:  Room 202, Lujiaxi Building

Abstract:

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 [1]. 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) [2], 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) [3], where the symmetry mismatch at the interface generates a spatially modulated strain field giving rise to a periodic pattern formation.

All 2-D oxide overlayers are prepared by a PVD method and are atomically characterized experimentally in a surface science approach by STM, LEED and various electron spectroscopies, as well as theoretically by extensive DFT calculations. 

[1] Oxide materials at the two-dimensional limit. F.P. Netzer and A. Fortunelli, Eds. (Springer Series in Materials Science, Vol. 234, Springer 2016)

[2]  N. Doudin, D. Kuhness, M. Blatnik, G. Barcaro, F.R. Negreiros, L. Sementa, A. Fortunelli, S. Surnev, F.P. Netzer, J. Phys. Chem.C 2016, 120, 28682

[3] L. Ma,  N. Doudin, S. Surnev, G. Barcaro,  L. Sementa, V. Mankad, A. Fortunelli, F.P. Netzer, J. Phys. Chem. Lett. 7(2016)1303