Regensburg 1998 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 1: Ladungseffekte in Einzelelektronensystemen

TT 1.1: Hauptvortrag

Montag, 23. März 1998, 09:30–10:00, H 19

Coulomb blockade in high-conductance tunnel junctions — •P. Joyez, V. Bouchiat, D. Esteve, and M.H. Devoret — Groupe quantronique SPEC, CE Saclay, 91191 Gif-sur-Yvette, France

We have investigated experimentally the lifting of Coulomb blockade in single and double tunnel junctions with tunnel conductances larger than the conductance quantum e²/h [1,2]. In both cases, we find that the main effect of increasing the tunnel conductance is to shift the Coulomb blockade regime towards lower temperatures. This effect is due to increased quantum charge fluctuations across the junction’s barrier and can be interpreted as a temperature-dependent increase of the junction’s capacitance. The behavior of a single junction is well captured by a mean-field treatment of the junction which will be detailed. For the double junction, dealing with discrete charge states requires a more elaborate treatment such as that of König et al [3].

[1] P. Joyez, V. Bouchiat, D. Esteve, C. Urbina, and M. H. Devoret, Phys. Rev. Lett. 79, 1349 (1997)

[2] P. Joyez, D. Esteve, and M. H. Devoret, preprint

[3] J. König, H. Schoeller, and G. Schön, Phys. Rev. Lett. 78, 4482 (1997)