Electronic properties and spin polarization in coupled quantum dots

Electronic structure and charging properties of an electrostatically define d double quantum dot system are investigated within the local spin density approximation under the density functional theory. Characteristics of elect ron charging of the double dot system is influenced by quantum-mechanical a s well as electrostatic coupling between the individual dots. In the case o f weak coupling, the double dot system is shown to exhibit double electron charging in agreement with the observations of Waugh et nl. [Phys. Rev. Let t. 75, 705 (1995)]. Also, the coupled dot system shows spin polarization fo r higher number of electrons in the dot N due to Hund's rule. For strong co upling, we show that coherent bonding and antibonding states are formed whi ch produce a reordering of the single-particle energy levels and revert the double dot system into a spin unpolarized state for same N.