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O: Fachverband Oberflächenphysik

O 86: Electronic Structure of Surfaces: Spectroscopy, Surface States II

O 86.3: Vortrag

Donnerstag, 20. März 2025, 15:30–15:45, H2

Quasi-particle interference studies on ultra-thin films of Cu(111) — •Jungin Yeo — Chung-Ang University, Seoul 06974, Republic of Korea

Recently, ultra-thin crystalline Cu(111) film has been successfully grown on a sapphire substrate through the atomic sputtering epitaxy (ASE). In-depth studies were conducted to explore the crystal growth mechanism and the oxidation process. Ultra-thin film without grain boundary (GB) shows hidden intrinsic nature such as transport by hole carriers. Meanwhile, twin boundaries (TB) appear inevitably during the growth even such an atomically high-quality film. As two orientations adjacent to a TB satisfy the symmetry operation exactly, TBs are expected to show different electronic properties from GBs. The unique electronic properties resulting from the two-dimensional nature and the presence of TBs are currently under investigation. For our study, we utilized scanning tunneling microscopy (STM) to examine 20 nm thick ASE-grown Cu(111) films. The STM topography revealed an atomically flat surface with an indication of twin boundaries. We performed quasi-particle interference (QPI) measurements across TBs. The surface states of Cu(111) and quantum-confined states within the film thickness were successfully resolved. By analyzing the QPI data, we were able to reconstruct the electronic dispersion near the Fermi energy, both at the surface and within the bulk of 20 nm thick. The transmission probability across TBs will be discussed.

Keywords: STM; Cu(111) electronic states; atomic sputtering epitaxy; twin boundary