SHUBNIKOV-DE HAAS OSCILLATIONS IN NEW ORGANIC CONDUCTORS (ET)(8)[HG4CL12(C6H5CL)(2)] AND (ET)(8)[HG4CL12(C6H5BR)(2)]

The results of the investigations of Shubnikov-de Haas oscillations in the quasi-two-dimensional organic complexes (ET)(8)[Hg4Cl12(C(6)H(5)X )(2)], where X = Cl, Pr in the magnetic fields up to 40 T were reporte d. These results allow one to obtain some information about Fermi surf ace in the mentioned complexes. Shubnikov-de Haas oscillations in the compound with X = Cl correspond at least to two different cylindrical sheets of Fermi surface with the cross-section in (bc)-plane of 13% an d 20% Brillouin zone cross-section. Shubnikov-de Haas oscillations in the complex with X = Pr correspond to one cylindrical sheet with the c ross-section in (bc)-plane of 13% of Brillouin zone cross-section. The experimental results for the complex with X = Br more agree with the theoretical calculations of Fermi surface than for the complex with X = Cl