Optical Polarization of Nuclear Spins in Silicon Carbide

We demonstrate optically pumped dynamic nuclear polarization of Si-29 nuclear spins that are strongly coupled to paramagnetic color centers in 4H- and 6H-SiC. The 99% +/- 1% degree of polarization that we observe at room temperature corresponds to an effective nuclear temperature of 5 mu K. By combining ab initio theory with the experimental identification of the color centers optically excited states, we quantitatively model how the polarization derives from hyperfine-mediated level anticrossings. These results lay a foundation for SiC-based quantum memories, nuclear gyroscopes, and hyperpolarized probes for magnetic resonance imaging.Funding Agencies|Air Force Office of Scientific Research (AFOSR); AFOSR Multidisciplinary Research Program of the University Research Initiative; National Science Foundation; Material Research Science and Engineering Center; Knut and Alice Wallenberg Foundation "Isotopic Control for Ultimate Materials Properties"; Lendulet program of the Hungarian Academy of Sciences; National Supercomputer Center in Sweden