Absence of correlation between built-in electric dipole moment and quantum Stark effect in single InAs/GaAs self-assembled quantum dots

We report significant deviations from the usual quadratic dependence of the ground-state interband transition energy on applied electric fields in single InAs/GaAs self-assembled quantum dots. While earlier works have used conventional second-order perturbation theory to claim a negative dipole moment in the presence of external electric field, we show that this theory fails to correctly describe the Stark shift for electric field below F=10kV/cm in high dots. Eight-band k⋅p calculations demonstrate that this effect is predominantly due to the three-dimensional strain field distribution which for various dot shapes and stoichiometric compositions drastically affect the hole ground state.