Alignment of the Diamond Nitrogen Vacancy Center by Strain Engineering

The nitrogen vacancy (NV) center in diamond is a sensitive probe of magnetic field and a promising qubit candidate for quantum information processing. The performance of many NV-based devices improves by aligning the NV(s) parallel to a single crystallographic direction. Using ab initio theoretical techniques, we show that NV orientation can be controlled by high-temperature annealing in the presence of strain under currently accessible experimental conditions. We find that $(89\pm7)\%$ of NVs align along the [111] crystallographic direction under 2\% compressive biaxial strain (perpendicular to [111]) and an annealing temperature of 970$^\circ$C.