Quantum phases in artificial molecules

The few-particle state of carriers confined in a quantum dot is controlled by the balance between their kinetic energy and their Coulomb correlation. In coupled quantum dots, both can be tuned by varying the inter-dot tunneli ng and interactions. Using a theoretical approach based on the diagonalizat ion of the exact Hamiltonian, we show that the transitions between differen t quantum phases can be induced through the inter-dot coupling both for a s ystem of few electrons (or holes) and for aggregates of electrons and holes . We discuss their manifestations, in addition energy spectra (accessible t hrough capacitance or transport experiments) and optical spectra. (C) 2001 Elsevier Science Ltd. All rights reserved.