Cyclotron Mass and Dingle Temperature of Conduction Electrons Moving in Layered Planes of Organic Superconductors: β-(BEDT-TTF)2IBr2, β-(BEDT-TTF)2I3and κ-(BEDT-TTF)2Cu(NCS)2

The cyclotron mass m c and the Dingle temperature T D in the layered planes of the organic superconductors are determined by the Shubnikov-de Haas effect at ambient pressure; m c =0.4 m 0 and T D =7–8 K, for β-(BEDT-TTF) 2 IBr 2 ( T c =2 K), and (0.4–0.5) m 0 and 11 K for β-(BEDT-TTF) 2 I 3 (=1 K), and 3.5 m 0 and (0.4±0.1) K for κ-(BEDT-TTF) 2 Cu(NCS) 2 ( T c =11 K). A systematic difference is clarified in m c and T D between these salts, suggestive of the origin of different T c 's among these salts.