Engineering coherent defects in diamond for quantum technologies

Abstract

Over the past two decades, diamond has emerged as a leading platform for hosting solid-state qubits like the nitrogen-vacancy (NV) center, a defect which features many applications in quantum information science involving quantum sensing, simulation, and computation. Chemical vapor deposition (CVD) diamond growth allows for creation of a high-quality lattice environment free from strain and paramagnetic impurities, which is ideal for probing the delicate nature of quantum coherence. CVD growth provides a route for creating NV centers through in-situ nitrogen doping followed by subsequent electron irradiation and annealing to enhance their concentration. This approach is desirable because it minimizes the lattice damage produced by ion implantation and also allows for improved control over the depth, density, and dimensionality of defect incorporation. For applications requiring shallow NV centers, the diamond surface poses a particular challenge to coherence, and preliminary work to protect a pristinely-prepared surface with dielectric capping layers is presented. Such efforts may allow for future experiments targeting interactions between NV centers and encapsulated adatoms, exploring the interface of an atom-defect hybrid quantum system.