Dresden 2017 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 63: Focus Session: Charge Transport at Surfaces and Nanostructures with Multi-probe Techniques
O 63.12: Poster
Dienstag, 21. März 2017, 18:30–20:30, P2-OG3
Metal-to-insulator transition in a quantum spin system — •Ilio Miccoli1, Frederik Edler1, Jan P. Stöckmann1, Bernd Hafke3, Michael Horn-von Hoegen3, Herbert Pfnür1,2, and Christoph Tegenkamp1,2 — 1Institut für Festkörperphysik, Hannover Uni., 30167-DE — 2Laboratory of Nano Quantum Engineering, Hannover, 30167-DE — 3CENIDE, Duisburg-Essen Uni., 47048-DE
Atomic wires on surfaces are prototype 1D systems for studying fundamental aspects, e.g. charge density waves (CDW) or dimensional crossover from a Fermi to a Luttinger liquid behavior. Among others, Au-induced wire structures on Si(553) substrates revealed a lot of attention because of their quasi-1D metallic structures with a pronounced magnetic order, which mimics a 2D quantum spin liquid state.[1] By means of low energy electron diffraction (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 isotropic order-disorder transition at 90 K, i.e. both the ×3 periodicity along and the magnetic ordering in between the wires vanishes simultaneously. In transport the system undergoes a metal-insulator transition (MIT). Thereby, while heating the resistance across the wires decreases sharply at 90K by 2-3 order of magnitude. Interestingly, we found also a MIT along the wires, which occurs at the same temperature. This combined study gives direct evidence also for a CDW formation along the wires. Moreover, the magnetic ordering stemming from localized electrons fed back to the 1D electronic states at Fermi energy.
B. Hafke et al., Phys. Rev. B 94 (2016) p. 161403