Extrinsic and Intrinsic Defects in MgO and CaO as potential spin-qubit candidates*

Several point defects in diamond, SiC, and h-BNhave been recently proposed as promising platforms to realize spin qubits. Here we extend the search of spin qubits to insulating oxides, as simple point defects in some binary and ternary oxides have been predicted to exhibit long coherence times [1]. We focus on intrinsic and extrinsic defects in MgO and CaO and present results for their structural, electronic, and optical properties. We consider the ubiquitous intrinsic oxygen and magnesium vacancies, and some of their complexes, and transition-metal and rare-earth dopants. To predict the strongly correlated excitations of these defects, we use the quantum defect embedding theory, an embedding approach that combines many-body perturbation theory to describe the valence electrons, with full-configuration interaction for the correlated electrons localized at the defect site [2].

1] Shun Kanai et al.: preprint arXiv:2102.02986 (2021).

[2] Nan Sheng, Christian Vorwerk, Marco Govoni, and Giulia Galli: preprint arXiv:2105.04736 (2021) and references therein.