Strain-induced g-factor tuning in single InGaAs/GaAs quantum dots

The tunability of the exciton g factor in InGaAs quantum dots using compressive biaxial stress applied by piezoelectric actuators is investigated. We find a clear relation between the exciton g factor and the applied stress. A linear decrease of the g factor with compressive biaxial strain is observed consistently in all investigated dots. A connection is established between the response of the exciton g factor to the voltage applied to the piezoelectric actuator and the response of the quantum dot emission energy. We employ a numerical model based on eight-band k⋅p theory to calculate the exciton g factor of a typical dot as a function of strain and a good agreement with our experiments is found. Our calculations reveal that the change in exciton g factor is dominated by the contribution of the valence band and originates from increased heavy hole light hole splitting when applying external stress

Active tuning of the g -tensor in InGaAs/GaAs quantum dots via strain

\u3cp\u3eDynamic control over the full g-tensor in individual InGaAs/GaAs self-assembled quantum dots is achieved by inducing external strain via a piezoelectric actuator. The full g-tensor is obtained by measuring in different geometries with different angles between an externally applied magnetic field and the quantum dot growth axes. A large decrease in the out-of-plane hole g-factor with strain is observed, whereas the other components are found to be less sensitive. To further investigate this, a numerical model based on eight-band k.p-theory is used and an excellent agreement with the experimental results is established, both qualitatively and quantitatively. Furthermore, the calculations reveal the origin of the observed large change in the out-of-plane hole g-factor to be the increase in heavy-hole light-hole splitting under compressive stress.\u3c/p\u3