Discrete charging of a quantum dot strongly coupled to external leadsR. Berkovits1, F. von Oppen2 and J. W. Kantelhardt3
1 The Minerva Center, Department of Physics, Bar-Ilan University Ramat-Gan 52900, Israel
2 Institut für Theoretische Physik, Freie Universität Berlin Arnimallee 14, 14195 Berlin, Germany
3 Institut für Theoretische Physik III, Justus-Liebig-Universität Giessen 35392 Giessen, Germany
received 19 May 2004; accepted 30 September 2004
published online 3 November 2004
We examine a quantum dot with levels which is strongly coupled to leads for varying number of channels N in the leads. It is shown both analytically and numerically that for strong couplings between the dot and the leads, at least bound states (akin to subradiant states in optics) remain on the dot. These bound states exhibit discrete charging and, for a significant range of charging energies, strong Coulomb blockade behavior as a function of the chemical potential. The physics changes for large charging energy, where the same (superradiant) state is repeatedly charged.
73.23.Hk - Coulomb blockade; single-electron tunneling.
71.15.Dx - Computational methodology (Brillouin zone sampling, iterative diagonalization, pseudopotential construction).
73.23.-b - Electronic transport in mesoscopic systems.
© EDP Sciences 2004