Self-assembled (In1−xMnx)As diluted magnetic semiconductor quantum dots with high Tc

Self assembled (In1−xMnx)As diluted magnetic semiconductor quantum dots (QDs) were grown on GaAs(1 0 0) substrates by using molecular beam epitaxy with a goal of producing (In1−xMnx)As QDs with a semiconductor phase and a high ferromagnetic transition temperature (Tc). High-resolution transmission electron microscopy measurements showed that crystalline (In0.84Mn0.16)As QDs were formed on GaAs substrates. Magnetic force microscopy images showed that the formed QDs were symmetric single-domain particles. The magnetization curve as a function of the magnetic field at 5 K indicated that the (In0.84Mn0.16)As QDs were ferromagnetic, and the magnetization curve as a function of the temperature showed that the Tc was as high as 400 K. These results indicate that (In0.84Mn0.16)As QDs grown on GaAs(1 0 0) substrates hold promise for potential applications in quantum bit devices operating at room temperature.