[1A04-09] Probe Microscopy 

4:00 PM - 4:30 PM JST(7:00 AM - 7:30 AM UTC)

[1A08【依頼講演】] Metallic States Emerging at Surface and Interfaces of β-FeSi₂/Si(001)

*Keisuke Sagisaka¹ (1. National Institute for Materials Science (NIMS) (Japan))

β-FeSi₂ is one of the most extensively studied semiconducting silicides because of its compatibility with silicon technology and its intriguing structural and electronic properties. Despite extensive investigations, the origin of surface metallicity and the atomic structure of the β-FeSi₂/Si(001) interface have remained unresolved. Our STM and DFT analyses establish the atomic structure of the Si-tetramer p(2×2) reconstruction on the β-FeSi₂(100) surface and reveal its role in generating metallic surface states. STS measurements show a finite density of states at the Fermi level, demonstrating metallicity of the reconstructed surface. Atomic-resolution STEM and DFT calculations further determine the β-FeSi₂/Si(001) interface structure and reveal metallic interface states originating from hybridization between Fe 3d orbitals and Si dimer states. These states form a two-dimensional electronic system confined to the interface. The results provide a unified picture of metallic states emerging at both the surface and the buried interface of β-FeSi₂/Si(001).

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