title: High-Fidelity Bidirectional Nuclear Qubit Initialization in SiC.
abstract: Dynamic nuclear polarization (DNP) is an attractive method for initializing nuclear spins that are strongly coupled to optically active electron spins because it functions at room temperature and does not require strong magnetic fields. In this Letter, we theoretically demonstrate that DNP, with near-unity polarization efficiency, can be generally realized in weakly coupled electron spin-nuclear spin systems. Furthermore, we theoretically and experimentally show that the nuclear spin polarization can be reversed by magnetic field variations as small as 0.8 Gauss. This mechanism offers new avenues for DNP-based sensors and radio-frequency free control of nuclear qubits.
authors.affiliation: Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping, Sweden.|Wigner Research Centre for Physics, Hungarian Academy of Sciences, PO Box 49, H-1525 Budapest, Hungary.
authors.forename: Viktor
authors.initials: V
authors.lastname: Ivády
authors.affiliation: Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA.
authors.forename: Paul V
authors.initials: PV
authors.lastname: Klimov
authors.affiliation: Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA.
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Miao
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.
authors.forename: David J
authors.initials: DJ
authors.lastname: Christle
authors.affiliation: Wigner Research Centre for Physics, Hungarian Academy of Sciences, PO Box 49, H-1525 Budapest, Hungary.
authors.forename: Krisztián
authors.initials: K
authors.lastname: Szász
authors.affiliation: Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping, Sweden.|Materials Modeling and Development Laboratory, National University of Science and Technology 'MISIS', 119049 Moscow, Russia.
authors.forename: Igor A
authors.initials: IA
authors.lastname: Abrikosov
authors.affiliation: Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, USA.
authors.forename: David D
authors.initials: DD
authors.lastname: Awschalom
authors.affiliation: Wigner Research Centre for Physics, Hungarian Academy of Sciences, PO Box 49, H-1525 Budapest, Hungary.|Department of Atomic Physics, Budapest University of Technology and Economics, Budafoki út 8., H-1111 Budapest, Hungary.
authors.forename: Adam
authors.initials: A
authors.lastname: Gali