Regensburg 2004 – scientific programme

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O: Oberflächenphysik

O 28: Postersitzung (Elektronische Struktur, Grenzfläche fest-flüssig, Halbleiteroberflächen und -grenzflächen, Magnetismus und Symposium SYXM, Methodisches, Nanostrukturen, Oberflächenreaktionen, Teilchen und Cluster, Zeitaufgelöste Spektroskopie)

O 28.45: Poster

Wednesday, March 10, 2004, 16:00–19:00, Bereich C

Pb on Si(557) - Steps towards a one-dimensional conductivity — •Ziad Kallassy, Martin Henzler, Heinz-Lorenz Günter, and Herbert Pfnür — Institut für Festkörperphysik,Applestrasse 2,30167 Hannover

The conductivity of ultrathin Pb films evaporated onto a highly stepped Si(557) surface was investigated by modified macroscopic 4-point measurements in UHV. After annealing 4 to 10 ML of Pb, evaporated at a sample temperature of 80K, to temperatures of 990K we obtained a strongly anisotropic conductivity at temperatures below 100K, with up to a factor of 20 higher conductance in the direction parallel to the step edges compared with the direction normal to them. While conductivity in this direction was found to be thermally activated and close to the conductivity of 1 ML of Pb on Si(111), it strongly decreases with increasing temperature in directions parallel to steps. The measurements will be correlated with LEED and STM results.