(e) Average of 15 line profiles taken parallel to the black line indicated in (d) through identical atomic positions. Both structures exhibit zig-zag chains of protrusions as a basic structural element. (d) Atomically resolved (15 nm ) 2 image with phase boundaries. Phase area assignment for the image from (a) by means of thresholding and height distribution. Brighter areas are associated with the ( 3 × 3 ) rect and darker regions with the ( 5 × 3 ) rect phase.
(a) Large scale (150 nm ) 2 image taken at a flat terrace showing the co-existence between two differently imaged phases. STM imaging for 0.365 ML Te on Cu(111) corresponding to the LEED-pattern of Fig. It turns out that the new ( 5 × 3 ) rect phase is the most dense surface telluride phase possible on Cu(111) before bulk-like copper telluride starts to grow. It also has by far the lowest energy of all models tested by DFT and simulated STM images agree perfectly with experiment. The presented structural model is verified by a LEED-IV analysis with Pendry R factor of R = 0.174 and quantitative agreement of structural parameters with DFT predictions. All Te atoms exhibit the same local sixfold coordination: They occupy threefold hollow sites of the substrate and are one-sided attached to another three Cu atoms. Additionally, the interspace between the troughs is decorated by Cu 2 Te 2 ad-chains sitting at hcp sites. We find that Te induces the formation of two-atom-wide zig-zag troughs within the Cu(111) top layer via replacing 4 Cu atoms per unit cell by two Te atoms.
It is structurally characterized by a combination of quantitative low-energy electron diffraction (LEED-IV), scanning tunneling microscopy (STM), and density functional theory (DFT). We present a so-far undetected submonolayer phase of copper telluride on Cu(111) with ( 5 × 3 ) rect periodicity and coverage of 0.40 ML tellurium (Te), which can be grown with perfect long-range order.
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