Characterization of the Si:Se+ spin-photon interface

TL;DR

This paper characterizes the Si:Se+ spin-photon interface in silicon, revealing strong optical dipole moments, long spin lifetimes, and promising radiative efficiency, advancing silicon-based quantum technologies.

Contribution

It provides detailed measurements of optical and spin properties of Si:Se+ donors, demonstrating their potential for integrated quantum photonic applications.

Findings

Optical transition dipole moment is 1.96 Debye.

Spin lifetime exceeds 4.6 hours at low magnetic fields.

Zero-phonon emission fraction is 16%.

Abstract

Silicon is the most developed electronic and photonic technological platform and hosts some of the highest-performance spin and photonic qubits developed to date. A hybrid quantum technology harnessing an efficient spin-photon interface in silicon would unlock considerable potential by enabling ultra-long-lived photonic memories, distributed quantum networks, microwave to optical photon converters, and spin-based quantum processors, all linked using integrated silicon photonics. However, the indirect bandgap of silicon makes identification of efficient spin-photon interfaces nontrivial. Here we build upon the recent identification of chalcogen donors as a promising spin-photon interface in silicon. We determined that the spin-dependent optical degree of freedom has a transition dipole moment stronger than previously thought (here 1.96(8) Debye), and the T1 spin lifetime in low magnetic fields is longer than previously thought (> 4.6(1.5) hours). We furthermore determined the optical excited state lifetime (7.7(4) ns), and therefore the natural radiative efficiency (0.80(9) %), and by measuring the phonon sideband, determined the zero-phonon emission fraction (16(1) %). Taken together, these parameters indicate that an integrated quantum optoelectronic platform based upon chalcogen donor qubits in silicon is well within reach of current capabilities.