Shubnikov-de Haas oscillations in an organic conductor tetramethyltetraselenafulvalene-2,5-dimethyl-7,7', 8,8' tetracyanoquinodimethane (TMTSF-DMTCNQ)

Abstract
The observation of Shubnikov-de Haas (SdH) oscillations in the metallic, high pressure phase (Metal-II) of TMTSF-DMTCNQ (P > 10 kbar) demonstrates the 3-dimensional, closed nature of the Fermi surface at low temperature (T < 2 K). We observe very small Fermi surface cross-sections of 1.16 x 1017 m-2 and 2.6 x 1017 m-2 in the ab and ac planes respectively. From the field and temperature dependence of the SdH oscillations we extract a cyclotron mass mc/m0 ≃ 0.56 and a Dingle temperature TD = 0.8 K. Finally we discuss the discrepancy between these results and the very high dc conductivity (σ 1.2K ≃ 3 x 105 (Ωcm)-1)