First-principles insights into the atomic structure of carbon-nitrogen-oxygen complex color centers in silicon

TL;DR

This paper uses first-principles calculations to identify atomic structures of spin-active color centers in silicon, proposing new defect configurations as potential quantum bits for telecom-band applications.

Contribution

It introduces novel atomic models for N-line series color centers in silicon, expanding the understanding of defect-based spin qubits for quantum technologies.

Findings

Proposes the N1 center consists of neighboring carbon and nitrogen interstitials.

Predicts complex defects involving oxygen and self-interstitials as candidates for other lines.

Suggests these centers are isoelectronic to the T-center and suitable for telecom applications.

Abstract

Spin-active color centers are the basis of solid-state defect systems utilized in quantum technologies. Although silicon is an emerging host material for quantum defects, there is an urgent need to characterize color centers with a non-zero electron-spin ground state in this platform, in addition to the prominent T-center. In this work, we carry out first-principles calculations to identify the possible atomic structures originating the experimentally observed N-line series in silicon. We propose that the core structure of the N1 center consists of a neighboring carbon and nitrogen interstitial atoms. Furthermore, we predict that more complex defects involving self-interstitial and interstitial oxygen atoms are feasible candidates for the further lines in the series. As all of these color centers are isoelectronic to the T-center, they provide a family of alternative spin qubits with emission near the low-energy telecommunication bands.