Asymmetry in self-assembled quantum dot-molecules made of identical InAs/GaAs quantum dots

Abstract

We show that a diatomic dot molecule made of two identical, vertically stacked, strained InAs/GaAs self-assembled dots exhibits an asymmetry in its single-particle and may-particle wavefunctions. The single-particle wave function is asymmetric due to the inhomogeneous strain, while the asymmetry of the many-particle wavefunctions is caused by the correlation induced localization: the lowest singlet ${}^1{\Sigma }_g$ and triplet ${}^3\Sigma$ states show that the two electrons are each localized on different dots within the molecule, for the next singlet states ${}^1{\Sigma }_u$ both electrons are localized on the same (bottom) dot for interdot separation $d>$ 8 nm. The singlet-triplet splitting is found to be $\sim 0.1$ meV at inter-dot separation $d$=9 nm and as large as 100 meV for $d$=4 nm, orders of magnitude larger than the few meV found in the large (50 - 100 nm) electrostatically confined dots.

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Cited by in corpus (3)

• Self-assembly of laterally aligned GaAs quantum dot pairs
• Singlet-triplet splitting, correlation and entanglement of two electrons in quantum dot molecules
• Electronic structures of (In,Ga)As/GaAs quantum dot molecules made of dots with dissimilar sizes