| Summary: | Engineering single atomic defects into wide bandgap materials has become an attractive field
in recent years due to emerging applications such as solid-state quantum bits and sensors. The
simplest atomic-scale defect is the lattice vacancy which is often a constituent part of more complex
defects such as the nitrogen-vacancy (NV) centre in diamond, therefore an understanding of the
formation mechanisms and precision engineering of vacancies is desirable. We present a theoretical
and experimental study into the ultra-fast laser generation of vacancy-interstitial pairs (Frenkel
defects) in diamond. In a range of other materials, Frenkel defect formation has previously been
linked to the recombination of laser generated excitonic states, however the mechanism in diamond
is currently unknown and to date no quantitative agreement has been found between experiment
and theory. Here, we find that a model for Frenkel defect generation via the recombination of
a bound biexciton as the electron plasma cools provides good agreement with experimental data.
The process is described by a set of coupled rate equations of the pulsed laser interaction with the
material and of the non-equilibrium dynamics of charge carriers during and in the wake of the pulse.
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