Scrambling and Gate Effects in Realistic Quantum Dots

Hong Jiang ¹, Denis Ullmo ^2, 3, Weitao Yang ¹, Harold U. Baranger ²

Physical Review B 71 (2005) 085313

We evaluate the magnitude of two important mesoscopic effects using a realistic model of typical quantum dots. « Scrambling\’\’ and « gate effect\’\’ are defined as the change in the single-particle spectrum due to added electrons or gate-induced shape deformation, respectively. These two effects are investigated systematically in both the self-consistent Kohn-Sham (KS) theory and a Fermi liquid-like Strutinsky approach. We find that the genuine scrambling effect is small because the potential here is smooth. In the KS theory, a key point is the implicit inclusion of residual interactions in the spectrum; these dominate and make scrambling appear larger. Finally, the gate effect is comparable in the two cases and, while small, is able to cause gate-induced spin transitions.

• 1. Department of Chemistry,
  Duke University
• 2. Duke Physics,
  Duke University
• 3. Laboratoire de Physique Théorique et Modèles Statistiques (LPTMS),
  CNRS : UMR8626 – Université Paris XI – Paris Sud