Dresden 2026 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 48: Metal & Semiconductor substrates: Structure, epitaxy and growth
O 48.3: Vortrag
Dienstag, 10. März 2026, 15:00–15:15, HSZ/0204
STM study of surface evolution and phase stability in Sn/Pt(111) systems — •Qing Shi, Fumio Komori, Masaki Mizuguchi, and Toshio Miyamachi — Nagoya University, Nagoya, Japan
The formation of Pt3Sn surface alloys on Pt(111) is of considerable interest for applications in catalysis and topological electronics. Depositing Sn on Pt(111) followed by annealing offers a route to realize atomically flat, single-crystalline Pt3Sn(111) surfaces suitable for detailed surface studies. Here, we reveal how the annealing process directly controls the surface morphology and local electronic structure in Sn/Pt(111) systems by scanning tunneling microscopy and spectroscopy (STM/S).
In the lower-temperature regime (< 400 K), where a Sn overlayer is stabilized, Sn atomic layers preferentially attach to step edges. The STS measurements indicate that the Sn overlayer is metallic due to hybridization with the Pt substrate. Upon annealing to higher temperatures, the surface undergoes Pt-Sn alloying, leading to the formation of a Pt3Sn phase across the surface. This transition is accompanied by pronounced island coarsening, morphological rounding, and an increase in local disorder, driven by thermally activated atom processes. Equilibrium shape analysis of the alloy islands reveals nearly isotropic step free energies, indicating minimal energetic differences between alternating A- and B-type step edges. Spectra acquired on the Pt3Sn terraces show a high density of states near the Fermi level, corresponding to contributions from both bulk and surface electronic states.
Keywords: Sn; Pt(111); Pt3Sn; superlattice; scanning tunneling microscopy