A LEEM study of structure, morphology and composition of ultrathin Ag/films on Pt(111)

Esther van Vroonhoven (Speaker), Poelsema, B. (Contributor)

Activity: Talk or presentationOral presentation

Description

The growth of ultra-thin silver films on Pt(111) at 750 K has been studied in real time and - space using Low Energy Electron Microscopy, LEEM. Our results demonstrate that the system is considerably more complex than appreciated so far. The LEEM/LEED results reveal a highly mobile film-substrate system. In the sub-monolayer regime they exhibit an intriguing sequence of surface confined alloying up till θ(Ag) = 0.5 ML and de-alloying (both consistent with existing literature), phase separation, partial strain relieve at θ(Ag) ~ 0.8 ML, reentrant alloying and accompanying build-up of strain as indicated by return of the monolayer film to the pseudomorphic state. During growth of the second layer more Pt is dissolved into the Ag-bilayer until the strain is finally relieved by the formation of wide trenches along <11-2> azimuth directions, in line with <1-10> being the soft direction under compressive strain. The full de-alloying and approach towards the bulk immiscibility of silver and platinum is reached only in third monolayer, accompanied by remarkable rearrangements at the interface.
Period27 Mar 2006
Event titleDPG Frühjahrstagung 2006 Dresden: (DPG Spring Meeting)
Event typeConference
LocationDresden, Germany
Degree of RecognitionInternational

Keywords

  • METIS-235985