Electronic coupling in InAs/GaAs self-assembled stacked double-quantum-dot systems

We have studied level splitting in systems consisting of two vertically aligned pyramidal InAs quantum dots embedded in GaAs. We have calculated and analyzed separately the contributions of the different effects that contribute to level splitting. First, we have shown that a simplified model considering only quantum-mechanical coupling between identical dots leads to significant level splitting only for a tip-to-base separation of less than 50 Angstrom. Then we added the effects of piezoelectricity and size difference between the two stacked dots to show that the resulting level splitting is considerably stronger than in the first model and could,in principle, be measured for much larger dot separations. [S0163-1829(98)02239-5].