Presentation Information
[8p-PB2-7]Core-level fingerprint of the In/Si(111)-B buried interface studied by first-principles calculations
〇Insung Seo1, Hiroyuki Kageshima1 (1.Shimane Univ.)
Keywords:
XPS,First-principles calculations,Thin film
Two-monolayer indium films on semiconductor surfaces are an important model system for studying the electronic properties of atomically thin metallic layers and their interaction with substrate interfaces. In particular, the In double-layer on Si(111) has attracted attention because the electronic states of the film can be modified by the atomic structure of the buried interface. For the Si(111)r3*r3-B substrate, the B-induced reconstruction provides a well-defined template, but the local termination of the interface beneath the In film remains a subtle issue. In particular, whether Si adatoms are retained at the interface or removed during the formation of the In film is difficult to determine from structural optimization alone. In this work, I investigate the In/Si(111)-B buried interface using first-principles calculations and simulated Si 2p X-ray photoelectron spectroscopy (XPS) fingerprints. First, density functional theory calculations were performed for In coverages from 1 to 4 monolayers on the no-adatom Si(111)-B interface model. The calculated incremental adsorption energies show that the addition of In atoms is favorable up to the formation of a two-monolayer film, whereas the third In layer becomes energetically unfavorable. This trend supports the stability of the In double-layer configuration and provides a useful reference for discussing the interfacial structure.Next, Si 2p core-level binding energies were calculated for different Si sites in the Si(111)-B substrate and the In-covered interface. The calculated spectra were decomposed into contributions from the Si adatom, first Si layer, second Si layer, and deeper Si layers. In the Si-adatom model, a characteristic high-binding-energy component appears from the adatom-related local environment. The detailed will be discussed in the presentation.