Current-induced control of the electron-nuclear spin system in semiconductors on a micrometer scale

The ability of using onchip microcoils to control the electron-nuclear spin system in semiconductors is demonstrated. Electrically generated magnetic fields of several tens of mT can be obtained on a micrometer length scale, which are switchable on a sub-ns time scale due to the low complex coil impedance. This allows one to electrically (i) manipulate the nuclear spins by means of nuclear magnetic resonance in n-GaAs and (ii) control the hyperfine flip-flop rate in CdSe/ZnSe quantum dots.