Berlin 2015 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 115: Metallic Nanowires on the Atomic Scale (jointly with DS, O)
TT 115.3: Talk
Friday, March 20, 2015, 10:15–10:30, H 2032
Transport in spatially confined anisotropic systems — •Frederik Edler1, Ilio Miccoli1,2, Herbert Pfnür1, and Christoph Tegenkamp1 — 1Institut für Festkörperphysik, Univ. Hannover, DE — 2Dept. Innovation Engineering, Univ. Salento, IT
Atomic chain ensembles are 1D-prototype systems with intriguing electronic properties, e.g. Peierls driven metal-insulator transitions (MIT). While such inherent instabilities can be probed smartly by surface transport, details of the phase transitions depend crucially on atomic-sized imperfections. In order to correlate such imperfections (including finite size effects) with transport properties, a spatial constriction of the electron paths is mandatory, e.g by using appropriately designed templates.
The In/Si(111) system reveals a strong anisotropy and has been comprehensively studied of the last years. We used it here as a benchmark system to investigate systematically the effects of confinement as well as of different contact geometries which is finally important to deduce correctly the resistivity components from resistance measurements. While spatial constrictions were achieved using Si(111)-mesas structures, various 4-point probe geometries could be realized by means of a 4-tip STM/SEM system. The anisotropy of the In-4× 1 has been quantified by rotating the tips gradually in squared configuration. Indeed, the sensitivity was increased by one order of magnitude by performing the transport experiments on confined areas. Furthermore, first studies of the MIT tuned by adsorption of, e.g. oxygen, have been performed and will be discussed.