Step-Terrace Morphology and Reactivity to C₆₀ of the Fivefold i-Ag-In-Yb Surface

Peter John Nugent (1) , Joe Smerdon (2) , Ronan Mcgrath (3) , Masahiko Shimoda (4) , Can Cui (4) , a Peter Tsai (4) , Hem Raj Sharma (2)

1 Physics
2 Physics
3 Physics
4 NIMS - National Institute for Materials Science

The surface of the icosahedral i-Ag-In-Yb quasicrystal provides one of the first non Al-based aperiodic surfaces that is suitable for study under ultra high vacuum conditions. We present a scanning tunneling microscopy (STM) study of the fivefold surface of this new quasicrystal demonstrating detailed structure of the terraces and steps. The analysis of the autocorrelation functions of STM images at opposite bias polarities and of the in-plane structure of the bulk model of i-Cd-Yb, which is isostructural to i-Ag-In-Yb, reveals that the surface terminations occur at the centres of the rhombic triacontrahedral (RTH) clusters, that are the basic building blocks of this material. The study further confirms that the occupied electronic states are enhanced at Ag/In sites and unoccupied states are located on Yb sites. Step edges display a Fibonacci sequence of truncated clusters, which can be also explained in terms of the model structure. Occasionally, a single terrace is found to display different structures at negative bias, whereas the same terrace show a uniform structure at positive bias. Depositing C₆₀ creates a disordered overlayer on the surface with no resulting FFT or LEED patterns.

Mots clés: Physical Sciences

Peter John Nugent, Joe Smerdon, Ronan Mcgrath, Masahiko Shimoda, Can Cui, et al.. Step-Terrace Morphology and Reactivity to C₆₀ of the Fivefold i-Ag-In-Yb Surface. Philosophical Magazine, 2010, pp.1. ⟨10.1080/14786435.2010.514870⟩. ⟨hal-00631270⟩