M\"ossbauer parameters of Fe-related defects in group-IV semiconductors: first principles calculations

TL;DR

This paper uses first-principles density functional calculations to interpret M"ossbauer spectroscopy data for iron-related defects in group-IV semiconductors, enabling accurate defect identification.

Contribution

It introduces a comprehensive methodology combining pseudopotential and all-electron calculations for analyzing M"ossbauer parameters in semiconductor defects.

Findings

Calculations agree with experimental data within 10% error.

Methodology can distinguish similar defect environments.

Provides accurate defect assignments in silicon.

Abstract

We employ a combination of pseudopotential and all-electron density functional calculations, to relate the structure of defects in supercells to the isomer shifts and quadrupole splittings observed in M\"ossbauer spectroscopy experiments. The methodology is comprehensively reviewed and applied to the technologically relevant case of iron-related defects in silicon, and to other group-IV hosts to a lesser degree. Investigated defects include interstitial and substitutional iron, iron-boron pairs, iron-vacancy and iron-divacancy. We find that in general, agreement between the calculations and M\"ossbauer data is within a 10% error bar. Nonetheless, we show that the methodology can be used to make accurate assignments, including to separate peaks of similar defects in slightly different environments.