Spin polarization in self-assembled quantum dots

Abstract

The spin properties of carriers in self-assembled quantum dots are studied theoretically using an empirical tight-binding method including spin-orbit coupling. Electrons and holes are found to reveal distinctive spin polarization: electron spin is found to follow the direction of the external magnetic field while hole spin is polarized along the growth direction of the dots. As a result, quasispins of electrons and holes are polarized along two perpendicular directions in a Voigt configuration and the circular polarization of emission from quantum dots quenches. The spin polarization of hole is responsible for a zero in-plane $g$ factor of holes in quantum dots. Our theoretical results successfully explain experiments.