Large nuclear Overhauser fields detected in vertically-coupled double quantum dots

Abstract

We report the electrical induction and detection of dynamic nuclear polarization in the spin-blockade regime of double GaAs vertical quantum dots. The largest Overhauser field observed was about 4 Tesla, corresponding to a nuclear polarization of about 40% in the present device. A phenomenological model is presented to provide a qualitative understanding of our results.

5 pages, 4 figures, rev-tex. Improved presentation of figures 1-3, also added SEM image to figure 1. Minor changes to discussion section, and added a concluding paragraph