Doubly Charged Silicon Vacancy Center, Si-N Complexes, And Photochromism In N And Si Codoped Diamond

Diamond samples containing silicon and nitrogen are shown to be heavily photochromic, with the dominant visible changes due to simultaneous change in total SiV0/- concentration. The photochromism treatment is not capable of creating or destroying SiV defects, and thus we infer the presence of the optically inactive SiV2- . We measure spectroscopic signatures we attribute to substitutional silicon in diamond, and identify a silicon-vacancy complex decorated with a nearest-neighbor nitrogen SiVN, supported by theoretical calculations.