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TT: Tiefe Temperaturen

TT 9: Mesoskopische Systeme

TT 9.1: Hauptvortrag

Dienstag, 28. März 2000, 10:00–10:30, H18

Not so small surprises in small supercondcutors — •A. K. Geim — University of Nijmegen, 6525 ED Nijmegen, The Netherlands

The superconducting coherence length describes the spatial extent of Cooper pairs, and superconductors of submicron size present a system somewhat similar to the one known as quantum dots. In the case of mesoscopic superconductors, it is Cooper pairs and vortices - rather than electrons - which are confined in a small box. I will overview our recent work [1] on magnetisation of individual micron-sized superconductors and show how we can measure energy spectra of an interacting as well as non-interacting Bose condensate in a small box in a magnetic field. Finally, I discuss the oxymoron of an intrinsic paramagnetism of ideal diamagnetics. [1] Nature v.390, 259 (1997); Nature v.396, 144 (1998).