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TT: Tiefe Temperaturen

TT 6: Postersitzung I (Amorphe- u. Tunnelsysteme, Niedrigdimensionale Systeme, Supraleitung: Elektronenstruktur, Phononen, Tunneln, Ordnungsparameter)

TT 6.24: Poster

Montag, 24. März 2003, 14:30–19:00, P2c, P2d

Analyzing the charging process to high electron densities on ⁴He films — •Johannes Voss, Andreas Würl, Jürgen Klier, and Paul Leiderer — Universität Konstanz, Fachbereich Physik, Fach M676, 78457 Konstanz

Electrons on ⁴He-films form two-dimensional electron systems (2DES). We gain the physical parameters of the 2DES through a transport measurement in the GHz range. While experiments with thick ⁴He-films (bulk) are reproducible and reliable, experiments using thin ⁴He-films (<50nm) are often disturbed by various effects. Given the fact that only thin ⁴He-films support higher electron densities, which are required to get access to the whole phase diagram (classical gas ⇔ Wigner crystal ⇔ degenerated Fermi gas), it is necessary to have a closer look to these effects and loss channels. Furthermore the question of determining the actual electron density is discussed. In the low density regime we can examine the Wigner crystallization by modifying parameters like the dielectric constant of the substrate, the microwave power or temperature. Going to higher electron densities we investigate non saturation, localization and tunneling effects. Reaching high electron densities we are searching for another phase transition, the so-called quantum melting. (The experiment is supported by the DFG, Forschergruppe "Quantengase")