Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 29: Metallic nanowires on semiconductor surfaces
O 29.7: Vortrag
Dienstag, 13. März 2018, 12:00–12:15, MA 144
Investigation of the phase transition in Si(553)-Au — •Frederik Edler1,2, Ilio Miccoli2, Herbert Pfnür2, and Christoph Tegenkamp1,2 — 1Institut für Festkörperphysik, Technische Universität Hannover, 09126 Chemnitz — 2Institut für Festkörperphysik, Leibniz Universität Hannover, 30167 Hannover
Atomic wires are prototype 1D systems for studying fundamental aspects, e.g. charge density waves or dimensional crossover from a Fermi to a Luttinger liquid behavior. Recently, the Si(553)-Au system revealed a lot of attention because of their quasi-1D metallic structures with pronounced magnetic order, mimicking a quantum spin liquid [1]. However, up to now the phase transition of this system is not completely understood. By means of LEED and 4-tip STM, we investigated the surface structure and transport properties of Si(553)-Au as a function of temperature.
LEED revealed an structural transition at TC=100 K, i.e. the × 3 periodicity along the wires vanishes. In contrast, upon cooling the resistance increases at 120 K across the wires sharply by 2-3 and along the wires by one order of magnitude in transport experiments. By systematic variation of the intrinsic doping levels for the Si-substrates we were able to disentangle space-charge layer from surface state contributions. The latter transport channel indeed showed a metal insulator transition at 65 K. However, we clearly rule out a metal insulator transition which is associated to the phase transition of the × 3 reconstruction.
B. Hafke et al., Phys. Rev. B. 94 (2016) p. 161403