Berlin 2024 – scientific programme

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O: Fachverband Oberflächenphysik

O 30: Poster: Proximity Effects in Epitaxial Graphene

O 30.6: Poster

Tuesday, March 19, 2024, 12:30–14:30, Poster A

Intercalation of Sn beneath the Buffer Layer on SiC(0001) studied by SPA-LEED — •Kurt Hered, Zamin Mamiyev, and Christoph Tegenkamp — Technische Universität Chemnitz, Institut für Physik, Reichenhainer Straße 70R

The intercalation of atomically flat metallic structures beneath epitaxial graphene is interesting for realizing proximity-coupled 2D systems. In this context, carbon group elements are noteworthy due to their well-known correlated electronic properties. In this work, we have investigated the intercalation of Sn beneath the buffer layer (BL) on 4H-SiC(0001) by means of high-resolution SPA-LEED. Superior to conventional LEED, SPA-LEED with its high k-space resolution and capability to investigate vertical and lateral roughness, enables control over the intercalation process. To optimize high-quality Sn-induced interface, we explore different routes, including varying Sn coverages, intercalation temperatures and time. It turns out that in all approaches, Sn intercalation progresses through intercalated disordered interface, an ordered 1×1 phase, and finally (√3×√3)R30^∘ periodicity w.r.t the SiC latticce, achieved above 1000 ^∘C. [1] Quantitative H(S) and G(S) analyses show for the clean system a mosaic two-level BL surface, with >97% BL with 2.5 Å  step heights, revealing a flat SiC surface at a 0.01^∘ inclination. After forming the Sn(1×1) interface layer, 95% transforms into QFMLG, with a slightly increased 2.64 Å  step height while preserving macroscopic surface orientation. Annealing above 1000 ^∘C results in surface roughening due to deintercalation. [1] Z. Mamiyev et al. Surf. Interfaces 34, 102304 (2022)

Keywords: Graphene; SPA-LEED; Intercalation; 2D materials; Proximity effects