Diamond nanowires with nitrogen vacancy under a transverse electric field

We have investigated the electronic, magnetic, and optical properties of hydrogenated diamond nanowires (DNWs) with nitrogen-vacancy (NV) centers using density functional theory. The strong localization of defect states results in the formation of local magnetic moments with a spin-polarization energy that is close to those for transition-metal atoms. Such spin-polarized defect states are found to be stable well above room temperature, in agreement with previous experimental reports. In addition, we find that a semiconductor-metal transition can be triggered upon applying a transverse electric field. Furthermore, an enhanced optical absorption in the visible-light region is predicted in DNWs with NV centers. The strength and the position of the absorption can be tuned or optimized by an external electric field and/or the nanowire diameter.