New Color Centers in Diamond for Quantum Networks*

Communication between quantum nodes is a key step in realizing the potential of quantum computers. However, this communication is fundamentally different from its classical analog, and so requires fundamentally new approaches - including new hardware. I will present recent efforts to engineer and characterize a promising new quantum resource - the neutral silicon vacancy (SiV⁰) in diamond.

SiV⁰ is a point defect in diamond, comprised of a substitutional silicon and a vacant carbon site. Point defects in diamond offer an atom-like system in a solid-state host with low magnetic noise. The nitrogen vacancy (NV) center has already been used to demonstrate several key elements of a quantum network; however, the optical transitions are not well-suited to network applications. Conversely, the negatively-charged silicon vacancy (SiV^-) has excellent optical properties, but poor spin coherence times. By carefully engineering the Fermi level of diamond, we are able to access a new silicon vacancy charge state, SiV⁰, which combines the long spin coherence times of NV (T_2,CPMG>200ms) and the favorable optical properties of SiV^-.