Condensed Matter Seminar

Stefan Rotter
Yale University

Thursday, February 14, 2008
1:00 pm in SPL 52

The Kondo Effect in a Mesoscopic Interacting Electron System

Abstract: We study the problem of a quantum dot with finite level spacing which is coupled anti-ferromagnetically to a Kondo spin ("Kondo box"). In particular, we investigate the influence of a ferromagnetic exchange interaction among the dot electrons. The problem is solved numerically by diagonalizing the system Hamiltonian in a good-spin basis and analytically in the weak and strong Kondo coupling limits. We discuss how the competition between the ferromagnetic exchange and the anti-ferromagnetic Kondo interaction affects the ground-state spin of the system. Finally, we explore the effect of an applied Zeeman field that can be used to probe experimentally the interplay between the exchange and Kondo interactions.