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TT: Fachverband Tiefe Temperaturen

TT 22: Transport: Poster Session

TT 22.28: Poster

Mittwoch, 27. Februar 2008, 14:00–18:00, Poster B

Resistance measurements on Bismuth nanowire arrays at low temperatures — •Thomas Kaupp¹, Christoph Kaiser², Georg Weiss¹, Thomas Cornelius³, and Reinhard Neumann³ — ¹Physikalisches Institut, Universität Karlsruhe, 76128 Karlsruhe, Germany — ²Institut für Mikro- und Nanoelektronische Systeme, Universität Karlsruhe, 76187 Karlsruhe, Germany — ³Gesellschaft für Schwerionenforschung, 64291 Darmstadt, Germany

Our sample fabrication started with creating nanoporous templates by exposing polymeric foils to heavy ion radiation. Into these templates, single- and poly-crystalline bismuth nanowires were electrochemically deposited. Resistance and magnetoresistance of arrays of these nanowires were studied at temperatures down to 50 mK. Additionally, aged samples of single-crystalline nanowires could be studied.

We observed a reduction of the resistance below 0.5 K of about 3 to 20 percent depending on the type of sample. The magnetoresistance of single-crystalline samples in this temperature range showed a linear behaviour up to 50 mT and then follows a power law with an exponent of 3/2 as previously reported. A linear magnetoresistance was observed for the poly-crystalline sample. The size of the linear increase up to 50 mT corresponds to the temperature dependent resistance reduction below 0.5 K.

Presently the interpretation of our observations is unclear. We discuss both the role of localization effects as well as the possibility that parts of the nanowires become superconducting.