Geometry and quantum delocalization of interstitial oxygen in silicon

TL;DR

This paper investigates the quantum delocalization of interstitial oxygen in silicon, accurately modeling its geometry and vibrational spectra, and discovering a new vibrational mode through first-principles calculations.

Contribution

It provides a detailed quantum mechanical analysis of interstitial oxygen in silicon, clarifying its geometry and vibrational properties with new computational insights.

Findings

Infrared absorption spectrum matches experimental bands at 517 and 1136 cm$^{-1}$.

Asymmetric lineshape of the 517 cm$^{-1}$ peak is well reproduced.

A new symmetric-stretching mode at 596 cm$^{-1}$ is identified.

Abstract

The problem of the geometry of interstitial oxygen in silicon is settled by proper consideration of the quantum delocalization of the oxygen atom around the bond-center position. The calculated infrared absorption spectrum accounts for the 517 and 1136 cm$^{-1}$ bands in their position, character, and isotope shifts. The asymmetric lineshape of the 517 cm$^{-1}$ peak is also well reproduced. A new, non-infrared-active, symmetric-stretching mode is found at 596 cm$^{-1}$. First-principles calculations are presented supporting the nontrivial quantum delocalization of the oxygen atom.