Interaction Effects in the Mesoscopic Regime: A Quantum Monte Carlo Study of Irregular Quantum Dots

Amit Ghosal 1, C. J. Umrigar 2, Hong Jiang 1, 3, Denis Ullmo 1, 4, Harold U. Baranger 1

Physical Review B 71 (2005) 241306

We address the issue of accurately treating interaction effects in the mesoscopic regime by investigating the ground state properties of isolated irregular quantum dots. Quantum Monte Carlo techniques are used to calculate the distributions of ground state spin and addition energy. We find a reduced probability of high spin and a somewhat larger even/odd alternation in the addition energy from quantum Monte Carlo than in local spin density functional theory. In both approaches, the even/odd effect gets smaller with increasing number of electrons, contrary to the theoretical understanding of large dots. We argue that the local spin density approximation over predicts the effects of interactions in quantum dots.

  • 1. Duke Physics,
    Duke University
  • 2. Laboratory of Atomic and Solid State Physics (LASSP),
    Cornell University
  • 3. Department of Chemistry,
    Duke University
  • 4. Laboratoire de Physique Théorique et Modèles Statistiques (LPTMS),
    CNRS : UMR8626 – Université Paris XI - Paris Sud