High-resolution spectroscopy of individual erbium ions in strong magnetic fields

In this paper, we use electrically detected optical excitation spectroscopy of individual erbium ions in silicon to determine their optical and paramagnetic properties simultaneously. We demonstrate that this high spectral resolution technique can be exploited to observe interactions typically unresolvable in silicon using conventional spectroscopy techniques due to inhomogeneous broadening. In particular, we resolve the Zeeman splitting of the $⁴\mathrm{I}_15/2$ ground and $⁴\mathrm{I}_13/2$ excited state separately, and in strong magnetic fields, we observe the anticrossings between Zeeman components of different crystal-field levels. We discuss the use of this electronic detection technique to aid in the identification of the symmetry and structure of erbium sites in silicon.