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 4I15/2 ground and 4I13/2 excited state separately and in strong magnetic fields we observe the anti-crossings between Zeeman components of different crystal field levels. We discuss the use of this electronic detection technique in identifying the symmetry and structure of erbium sites in silicon.