Fermi surface in the new organic quasi-two-dimensional metal alpha-(BETS)(2)TlHg(SeCN)(4)

Quantum oscillations of de Haas-van Alphen and Shubnikov-de Haas and semiclassical angular oscillations of the magnetoresistance have been observed in the quasi-two-dimensional organic metal α-(BETS)2TlHg(SeCN)4. The quantum oscillations are connected with the cylindrical part of the Fermi surface. The angular oscillations are associated with the carrier motion on both the cylindrical part and quasi-planar sheets of the Fermi surface. The values of the Dingle temperature, TD ≈ 2–3 K, and the effective mass, m* ≈ 1.03m0, have been defined. The possibility of the weakening of multibody interactions has been shown in this compound.