Coherent control of a single spin with electric fields

We experimentally realize coherent control of a single electron spin in a quantum dot using an ac electric field generated by a local gate. The electric field induces coherent transitions (Rabi oscillations) between spin-up and spin-down, whereby the rotation angle is controlled by the amplitude and duration of the electric field bursts. We find a strong dependence of the Rabi frequency on the static magnetic field, with 90◦ rotations as fast as ∼55 ns at 2.8 T. Our analysis indicates that the electrically-induced spin transitions are mediated by the spin-orbit interaction. These results, together with the recently demonstrated coherent exchange of two neighboring spins, demonstrate the feasibility of fully electrical manipulation of spin qubits.