Regensburg 2002 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 12: Niedrigdimensionale Systeme, Magnetotransport II

TT 12.7: Vortrag

Dienstag, 12. März 2002, 16:30–16:45, H18

Shubnikov-de Haas effect in quasi-two-dimensional metals — •Mark Kartsovnik¹, Pavel Grigoriev^2,3, Werner Biberacher¹, Andreas Gröger³, and Dieter Andres¹ — ¹Walther-Meissner-Institut, Walther-Meissner-Str. 8, 85748 Garching, Germany — ²HMFL, MPI-CNRS, BP 166, 38042 Grenoble, France — ³Landau Institute for Theoretical Physics, 142432 Chernogolovka, Russia

We analyze the Shubnikov-de Haas effect in the interlayer magnetoresistance of the layered organic metal β-(BEDT-TTF)₂IBr₂ under the conditions when the cyclotron energy ℏω_c is comparable to the interlayer transfer integral t. The beats of the SdH oscillations originated from a slight warping of the cylindrical Fermi surface are considerably shifted with respect to those of the magnetisation oscillations. The shift is determined by the ratio ℏω_c/t that may lead to significant deviations from the conventional periodicity of the beats in the 1/B scale. Further, the warping of the Fermi surface gives rise to slow oscillations which are virtually independent of temperature. As a result, they can be observed at relatively high temperatures at which the fundamental SdH oscillations are completely suppressed by the temperature damping factor.