Nuclear-spin-induced oscillatory current in spin-blockaded quantum dots.

We show experimentally that electron transport through GaAs-based double quantum dots can be affected by ambient nuclear spin states in a certain regime where transport is blocked in the absence of electron spin flip. Current through the dots oscillates in time with a period up to 200 s depending on magnetic field. Oscillation is quenched by application of a continuous wave ac magnetic field which can induce nuclear magnetic resonance in 71Ga or 69Ga. A possible mechanism for dynamically polarizing the nuclear spins is proposed.