  The 2D Fermi surface of 1st stage PdAl2Cl8 acceptor-type graphite
intercalation compounds (GICs) has been investigated using the Shubnikov-de
Haas (SdH) effect. One fundamental frequency is observed, the angular variation
of which confirms its strongly 2D nature, as previously found through
electrical conductivity measurements. The energy spectrum can be described by
the 2D band structure model proposed by Blinowski et al. We obtain the
following parameter values: intraplane C-C interaction energy gamma_0 = 2.7 eV,
Fermi energy E_F = -1.1 eV and carrier density n_SdH= 1.1x10^27 m^-3. Some
fewer details are presented on stage 2 and 3 materials.
