Core-Level Photoelectron Spectroscopy Probing Local Strain at Silicon Surfaces and Interfaces

TL;DR

This study uses first-principles calculations and photoelectron spectroscopy to analyze local strain at silicon surfaces and interfaces, revealing how atomic-scale strain influences spectral features.

Contribution

It introduces a method combining first-principles calculations and Wannier functions to distinguish strain effects from electronegativity influences in silicon spectra.

Findings

Good agreement between calculated and measured spectra.

Photoelectron spectroscopy can directly measure atomic-scale strain.

Distinguished effects of electronegativity and local strain on spectra.

Abstract

Using a first-principles approach, we investigate the origin of the fine structure in Si 2$p$ photoelectron spectra at the Si(100)2$\times$1 surface and at the Si(100)-SiO$_2$ interface. Calculated and measured shifts show very good agreement for both systems. By using maximally localized Wannier functions, we provide an interpretation in which the effects due to the electronegativity of second nearest neighbor atoms and due to the local strain field are distinguished. Hence, in combination with accurate modeling, photoelectron spectroscopy can provide a direct measure of the strain field at the atomic scale.