Characterization of the spin and crystal field Hamiltonian of erbium dopants in silicon

TL;DR

This study provides a detailed characterization of erbium dopants in silicon, including their spin and crystal field Hamiltonians, to optimize their use in quantum photonic devices.

Contribution

It offers a comprehensive analysis of erbium sites in silicon, reconstructing the spin Hamiltonian and constraining dopant locations for improved quantum memory integration.

Findings

Determined site symmetry of erbium in silicon.

Reconstructed the spin Hamiltonian of erbium sites.

Constrained dopant location within silicon lattice.

Abstract

The integration of coherent emitters into low-loss photonic circuits is a key technology for quantum networking. In this context, nanophotonic silicon devices implanted with erbium are a promising hardware platform that combines advanced wafer-scale nanofabrication technology with coherent emission in the minimal-loss band of optical fibers. Recent studies have reported two distinct sites in the silicon lattice in which erbium can be reproducibly integrated with particularly promising properties. Here, for an in-depth analysis of these sites, resonant fluorescence spectroscopy is performed on a nanophotonic waveguide in magnetic fields applied along different orientations. In this way, the site symmetry is determined, the spin Hamiltonian is reconstructed and a partial fit of the crystal field Hamiltonian is performed. The obtained quantitative description of the magnetic interaction allows the optimization of Zeeman splittings, optical branching ratios or microwave driving to the needs of future experiments. Beyond that, the derived site symmetry constrains the location of the erbium dopant in the silicon unit cell. This is a key step towards a detailed microscopic understanding of the erbium sites, which may help to improve the integration yield, thus paving the way to efficient nanophotonic quantum memories based on the Er:Si platform.