Polarizing nuclear spins in quantum dots by injection of a spin-polarized current.

We demonstrate spin-polarization of the nuclei in self-assembled InGaAs quantum dots due to electrical injection of a spin-polarized current. High-resolution optical spectroscopy of the Overhauser shift is used as detection method. The electrically induced spin-polarization is of comparable magnitude as for spin-injection by photoexcitation. The results imply that efficient nuclear spin-polarization in quantum dots can be achieved by purely electrical means. [ABSTRACT FROM AUTHOR]