We show that electron and hole Landé $g$ factors in self-assembled III-V quantum dots have a rich structure intermediate between that of paramagnetic atomic impurities and bulk semiconductors. Strain, dot geometry, and confinement energy modify the effective $g$ factors, yet are insufficient to explain our results. We find that the dot’s discrete energy spectrum quenches the orbital angular momentum, pushing the electron $g$ factor towards 2, even when all the materials have negative bulk $g$ factors. The approximate shape of a dot can be determined from measurements of the $g$ factor asymmetry.

• Received 27 October 2004

DOI:https://doi.org/10.1103/PhysRevLett.96.026804