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

TL;DR

This study reveals that the quantum Stark effect in InAs/GaAs quantum dots deviates from quadratic behavior due to strain effects, challenging traditional perturbation theory and supported by experimental evidence.

Contribution

It demonstrates that strain distribution significantly influences the Stark effect in quantum dots, highlighting limitations of conventional models.

Findings

Deviations from quadratic Stark shift in quantum dots

Strain distribution affects hole ground state

Experimental validation supports theoretical results

Abstract

We report significant deviations from the usual quadratic dependence of the ground state interband transition energy on applied electric fields in InAs/GaAs self-assembled quantum dots. In particular, we show that conventional second-order perturbation theory fails to correctly describe the Stark shift for electric field below $F = 10$ kV/cm in high dots. Eight-band ${\bf k}\cdot{\bf p}$ calculations demonstrate this effect is predominantly due to the three-dimensional strain field distribution which for various dot shapes and stoichiometric compositions drastically affects the hole ground state. Our conclusions are supported by two independent experiments.