de Haas-van Alphen oscillations in the quasi-two-dimensional organic conductor κ-(ET)2Cu(NCS)2:: The magnetic breakdown approach -: art. no. 165102

We present both experimental data and an analytic theory for the de Haas-van Alphen (dHvA) effect in the two-dimensional organic single-crystal conductor kappa-(ET)(2)Cu(NCS)(2). We show that the magnetization oscillation pattern and the fast Fourier transform (FFT) spectrum of our measurements are well described theoretically within the coherent magnetic breakdown (MB) model for a two-dimensional Fermi surface consisting of two open sheets and closed pockets connected by magnetic breakdown centers. The spectrum of Landau quantized energy levels changes substantially due to the MB. Landau bands develop whose bandwidth and relative distance between them oscillate in inverse magnetic field. These oscillations explain the observed fine structure of the magnetization pattern at fields above the MB field with the occurrence of "forbidden" frequencies in the FFT spectrum.