Anisotropic electron spins in self-assembled quantum dots

Electron g-factors in self-assembled InAs/GaAs quantum dots are studied theoretically by means of a tight-binding method. The anisotropy in the electron g-factor, induced by the band-mixing effect, is found to be much more sensitive to the chemical composition of the dot than the aspect ratio of the structure. The modulus of the vertical electron g-factor is usually seen smaller than the in-plane component in pure InAs dots while the situation could be reversed in highly intermixing InGaAs dots. A microscopic theory is presented to reveal the dependence of the anisotropy in the electron g-factor on the proportion of the valence-band components in the electronic states. Our study indicates the possibility of tuning electron g-factor anisotropy in quantum dots.