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Mechanism of formation of a 2D binary alloy

L. Ottaviano·G. Profeta·L. Petaccia·C. Nacci·S. Santucci·A. Pesci·M. Pedio
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Abstract

Direct comparison of scanning tunneling microscopy and high resolution core level photo-emission experiments provides a rationale for the mechanism of formation of a two dimensional (2D) binary alloy (1/3 mono-layer (ML) Sn(1- x)Six/Si(111)-\sqrt3X\sqrt3R30). In contrast with recent theoretical predictions, the pure metal surface (x=0) results partitioned into two classes (2/9 ML and 1/9 ML) of ad-atoms occupying non-equivalent T4 sites. During the formation of the alloy, Si ad-atoms preferably occupy the majority type adsorption site. This peculiar substitution mechanism leads to a mutual arrangement of ad-atoms which is not random even at room temperature, but shows the typical short range order universally observed in 2D and quasi 2D binary alloys

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L. Ottaviano, G. Profeta, L. Petaccia, C. Nacci, S. Santucci, A. Pesci, M. Pedio. 2001-03-27. Mechanism of formation of a 2D binary alloy. https://arxiv.org/abs/cond-mat/0103568

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