Parallel preparation of highly spin-polarized electrons in single InAs∕GaAs quantum dots

Abstract

Initialization of electron spins in semiconductor quantum dots (QDs) is a major prerequisite for a successful implementation of such QDs in quantum information applications. It is essential that the initialization is achieved for many individually separable dots in parallel. Here the authors show that exactly this can be accomplished with near-unity fidelity by electrical spin injection from the diluted magnetic semiconductor ZnMnSe into InAs∕GaAs quantum dots. The deviation from unity is smaller than 0.13, more precise determination is limited by the signal-to-noise ratio of their setup. They demonstrate the robust concurrent initialization of several quantum dots with the same high fidelity.