Anisotropic nature of hole g-factor in individual InAs quantum rings

Abstract

The in-plane g-factors of electron and hole spins (g perpendicular to e, g perpendicular to h) confined in the individual InAs/GaAs quantum rings (QRs) were investigated by using experimental and theoretical approaches. From the measurements, we found that the experimentally obtained \g perpendicular to h\varies largely from QR to QR, while the variation in \g perpendicular to e\ is small. In addition, the in-plane (x-y) and the out-of-plane (x-z) anisotropies in hole g-factor were obviously confirmed while the electron g-factor exhibits isotropic natures in both cases. From the model calculations, the effects of the shape anisotropies and the uniaxial stress were examined. The shape anisotropy in QRs modifies the spatial distributions of hole wavefunctions. Thus, it brings the resultant changes in the degree of valence-band mixing and \g perpendicular to h\, and combined with uniaxial stress, a larger modulation in \g perpendicular to h\ was achieved. Although more detailed discussions are necessary at this stage, our findings will give valuable information for the g-factor control in semiconductor nanostructures.