Exact diagonalization and Quantum Monte Carlo studies of quantum dots

摘要

We report exact diagonalization and diffusion quantum Monte Carlo calculations of quantum dots (QDs) in which energetics due to electron-electron interactions, magnetic field, and geometrical factors compete and induce interesting ground state configurations. The geometrical effects are generated by different confining potentials such as parabolic shaped, ring shaped, and disordered potentials. The addition spectra, spin configurations and Hund's rules are investigated for QDs containing up to 13 strongly interacting electrons. In addition to the familiar Coulomb and spin blockades, a new transport blockade is predicted when the electrons are spatially localized in different potential minima. While the transition energy between spin states is found to be affected by the disorder, closed shell Hund's rule is maintained for the disorder strength considered here.