Regensburg 2007 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 1: Superconductivity - Fabrication and Characterization
TT 1.3: Vortrag
Montag, 26. März 2007, 10:00–10:15, H18
Phase Slip in Thin Superconducting Wires — •Jonathan Eroms, Toeno van der Sar, Manohar Kumar, Ad Verbruggen, Kees Harmans, and Hans Mooij — Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 50 46, NL-2600GA Delft, The Netherlands
We experimentally investigate thermal and quantum phase slip in thin wires of amorphous NbSi. Quantum phase slip could ultimately be employed in a new type of superconducting qubit, but clear experimental evidence is scarce up to now. We focus on sputtered NbSi films with lithographically defined wires, since this will offer more flexibility for more complex devices. The sheet resistance, transition temperature and long-term stability of various film compositions and thicknesses were studied. The wires are fabricated with high-resolution e-beam lithography, using HSQ resist, a Leica EBPG 5000+ lithography tool and SF6/He-based reactive ion etching. Line widths down to less than 15 nm are achievable. Transport in the wires was measured in a 3He-cryostat, and also in a dilution refrigerator with extensive filtering. Wires with a normal state resistance per length of more than 35 Ω/nm deviate from the LAMH theory of thermally activated phase slip and show a saturation of the resistance at low temperature, which could point to quantum phase slip.