title: Dynamic nuclear polarization with single electron spins.
abstract: We polarize nuclear spins in a GaAs double quantum dot by controlling two-electron spin states near the anticrossing of the singlet (S) and m(S)= +1 triplet (T+) using pulsed gates. An initialized S state is cyclically brought into resonance with the T+ state, where hyperfine fields drive rapid rotations between S and T+, "flipping" an electron spin and "flopping" a nuclear spin. The resulting Overhauser field approaches 80 mT, in agreement with a simple rate-equation model. A self-limiting pulse sequence is developed that allows the steady-state nuclear polarization to be set using a gate voltage.
authors: Department of Physics, Harvard University, 17 Oxford St., Cambridge, Massachusetts 02138, USA.
authors: J R
authors: JR
authors: Petta
authors: J M
authors: JM
authors: Taylor
authors: A C
authors: AC
authors: Johnson
authors: A
authors: A
authors: Yacoby
authors: M D
authors: MD
authors: Lukin
authors: C M
authors: CM
authors: Marcus
authors: M P
authors: MP
authors: Hanson
authors: A C
authors: AC
authors: Gossard