Electronic structure of vertically coupled double quantum dots: Optimization of basis functions

► We have performed an exact diagonalization calculation for electronic structure of vertically coupled double quantum dots using linear combination of atomic orbitals. ► We find that to reach high accuracy of results and get a quick convergence, a special attention in choice of basis functions has to be paid, specially for small quantum dots. ► We also find the character of electronic states of double quantum dots evolves from atomic-like to molecular characteristic (bounding and anti-bounding) states as interdot distance decreases. ► Finally, we show that the electronic structure of double quantum dots (DQD) can be engineered through properly DQD design.