Quantum bit with telecom wave-length emission from a simple defect in Si

TL;DR

This paper demonstrates that a simple carbon interstitial defect in silicon can emit telecom-wavelength photons and potentially serve as a quantum bit with a spin-to-photon interface in CMOS-compatible platforms.

Contribution

The study provides a theoretical and experimental analysis confirming the defect's emission properties and its potential as a quantum bit in silicon-based quantum communication.

Findings

Emission due to recombination of a bound exciton

Presence of a metastable triplet state for quantum memory

Potential for spin-to-photon interface in silicon

Abstract

Spin-to-photon interfaces from defects in silicon hold great promise towards realizing quantum repeaters with the combination of advanced semiconductor and photonics technologies. Recently, controlled creation and erasure of simple carbon interstitial defects have been successfully realised in silicon. This defect has a stable structure near room temperature and emits in the wave-length where the signal loss is minimal in optical fibres used in communication technologies. Our in-depth theoretical characterization confirms the assignment of the observed emission to the neutral charge state of this defect. We find that the emission is due to the recombination of a bound exciton. We also discovered a metastable triplet state that could be applied as a quantum memory. Based on the analysis of the electronic structure of the defect and its similarities to a known optically detected magnetic resonance centre in silicon, we propose that a carbon interstitial can act as a quantum bit and may realize a spin-to-photon interface in CMOS-compatible platforms.