Suppressing spin qubit dephasing by nuclear state preparation.
Coherent spin states in semiconductor quantum dots offer promise as electrically controllable quantum bits (qubits) with scalable fabrication. For few-electron quantum dots made from gallium arsenide (GaAs), fluctuating nuclear spins in the host lattice are the dominant source of spin decoherence. We report a method of preparing the nuclear spin environment that suppresses the relevant component of nuclear spin fluctuations below its equilibrium value by a factor of approximately 70, extending the inhomogeneous dephasing time for the two-electron spin state beyond 1 microsecond. The nuclear state can be readily prepared by electrical gate manipulation and persists for more than 10 seconds.
Reilly
D J
DJ
Department of Physics, Harvard University, Cambridge, MA 02138, USA.
Taylor
J M
JM
Petta
J R
JR
Marcus
C M
CM
Hanson
M P
MP
Gossard
A C
AC