Electrical spin pumping of quantum dots at room temperature

Abstract

We report on electrical control of the spin polarization of $\mathrm{In}\mathrm{As}∕\mathrm{Ga}\mathrm{As}$ self-assembled quantum dots (QDs) at room temperature. This is achieved by electrical injection of spin-polarized electrons from an Fe Schottky contact. The circular polarization of the QD electroluminescence shows that a 5% electron spin polarization is obtained in the InAs QDs at $300\mathrm{K}$ , which is remarkably insensitive to temperature. This is attributed to suppression of the spin-relaxation mechanisms in the QDs due to reduced dimensionality. These results demonstrate that practical regimes of spin-based operation are clearly attainable in solid-state semiconductor devices.