title: Optical Polarization of Nuclear Spins in Silicon Carbide.
abstract: We demonstrate optically pumped dynamic nuclear polarization of (29)Si 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  μK. 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.
authors.affiliation: Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA.|IBM T. J. Watson Research Center, Yorktown Heights, New York 10598, USA.
authors.forename: Abram L
authors.initials: AL
authors.lastname: Falk
authors.affiliation: Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA.|Department of Physics, University of California, Santa Barbara, Santa Barbara, California 93106, USA.
authors.forename: Paul V
authors.initials: PV
authors.lastname: Klimov
authors.affiliation: Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, H-1525 Budapest, Hungary.|Department of Physics, Chemistry, and Biology, Linköping University, SE-581 83 Linköping, Sweden.
authors.forename: Viktor
authors.initials: V
authors.lastname: Ivády
authors.affiliation: Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, H-1525 Budapest, Hungary.|Institute of Physics, Loránd Eötvös University, H-1117 Budapest, Hungary.
authors.forename: Krisztián
authors.initials: K
authors.lastname: Szász
authors.affiliation: Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA.|Department of Physics, University of California, Santa Barbara, Santa Barbara, California 93106, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Christle
authors.affiliation: Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA.
authors.forename: William F
authors.initials: WF
authors.lastname: Koehl
authors.affiliation: Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, H-1525 Budapest, Hungary.|Department of Atomic Physics, Budapest University of Technology and Economics, H-1111 Budapest, Hungary.
authors.forename: Ádám
authors.initials: Á
authors.lastname: Gali
authors.affiliation: Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA.
authors.forename: David D
authors.initials: DD
authors.lastname: Awschalom