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TT: Tiefe Temperaturen

TT 25: Postersitzung III: Pinning und Vortexdynamik, Massive HTSL, Bandleiter, Transporteigenschaften in HTSL, SL dünner Filme, Elektronen und Phononen in HTSL, Tunneln, Borkarbide, Quantenphasen und Metall-Isolator-Überg
änge, Anwendungen, Sonstiges

TT 25.60: Poster

Donnerstag, 29. März 2001, 14:30–17:00, Rang S\ 3

Metal-insulator transition in icosahedral Al-Pd-Re films — •Roland Haberkern¹, Ralph Rosenbaum², and Peter Häussler¹ — ¹TU Chemnitz, 09107 Chemnitz — ²Tel Aviv University, Ramat Aviv, 69978, ISRAEL

It is still controversially discussed if there exists an insulating behaviour of bulky i-Al-Pd-Re. By means of co-sputtering we prepared a set of films with high homogeneity for the individual samples and a systematic and slightly changing composition from one sample to the next. The i-films show an electrical conductivity σ, systematically changing with composition from metallic (small, but finite conductivity for T → 0 K) to weakly insulating and back to metallic behaviour again. The temperature dependence σ(T) for 0.1 K < T< 4 K of the most insulating samples can be attributed to activated hopping. This result is astonishing, as the surface of a quasicrystal is believed to be metallic and should contribute significantly to the conductivity of our films with a thickness of 220 nm.