Interactions and Interference in Quantum Dots: Kinks in Coulomb Blockade Peak Positions

Harold U. Baranger 1, 2, Denis Ullmo 3, Leonid I. Glazman 4

Physical Review B 61 (2000) R2425-2428

We investigate the spin of the ground state of a geometrically confined many-electron system. For atoms, shell structure simplifies this problem-- the spin is prescribed by the well-known Hund's rule. In contrast, quantum dots provide a controllable setting for studying the interplay of quantum interference and electron-electron interactions in general cases. In a generic confining potential, the shell-structure argument suggests a singlet ground state for an even number of electrons. The interaction among the electrons produces, however, accidental occurrences of spin-triplet ground states, even for weak interaction, a limit which we analyze explicitly. Variaton of an external parameter causes sudden switching between these states and hence a kink in the conductance. Experimental study of these kinks would yield the exchange energy for the ``chaotic electron gas''.

  • 1. Bell Laboratories, Lucent Technologies,
    Bell Laboratories
  • 2. Duke Physics,
    Duke University
  • 3. Laboratoire de Physique Théorique et Modèles Statistiques (LPTMS),
    CNRS : UMR8626 – Université Paris XI - Paris Sud
  • 4. Theoretical Physics Institute,
    University of Minnesota