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O: Fachverband Oberflächenphysik

O 75: Metal Substrates: Growth Studies

O 75.2: Vortrag

Mittwoch, 18. März 2020, 15:15–15:30, WIL C107

Submonolayer growth of Te on Cu(111) — •Tilman Kißlinger, Andreas Raabgrund, Maximilian Ammon, M. Alexander Schneider, and Lutz Hammer — Lehrstuhl für Festkörperphysik, Universität Erlangen–Nürnberg, D–91058 Erlangen, Germany

Tellurium (Te) based alloys play an important role in metallurgy, thermoelectricity and photovoltaics [1]. Thus, an accurate knowledge of the crystallographic surface structure and elemental composition of such systems is the first step to any understanding of their diverse physical properties. We studied the adsorption of Te on Cu(111) for submonolayer coverages with quantitative low-energy-electron diffraction (LEED), scanning tunneling microscopy (STM) and density-functional theory (DFT).

Below Θ=1/12 ML we find Te atoms to form a disordered structure. Above this threshold a (2√3 × √3)R30^∘ structure evolves that is fully developed at a coverage of 1/3 ML. STM shows a well-ordered surface phase that is solved by our LEED-analysis (Δ E = 8.7 keV, R = 0.127) to consist of Te₂Cu₂ chains in hcp-sites of the first substrate layer in perfect agreement with the structure calculated by DFT. Furthermore, we show that the finding of a ( √3 × √3)R30^∘ structure at similar coverages reported in [2] is the consequence of an adsorbate induced phase transition as observed e.g. for H₂ or CO.

[1]: Ibers J., Nat. Chem. 1, 508 (2009)
[2]: Lahti et al., Surf. Sci. 622, 35 (2014)