Fermi surface studies in the magnetic-field-induced superconductor λ − ( BETS ) 2 FeCl 4

Measurements of the Shubnikov\char21{}de Haas (SdH) and angular-dependent magnetoresistance oscillations were performed to study the Fermi surface for a magnetic-field-induced superconductor $\ensuremath{\lambda}\ensuremath{-}(\mathrm{BETS}{)}_{2}{\mathrm{FeCl}}_{4}.$ We found two SdH oscillations ascribed to the minimum and maximum cross-sectional areas of corrugated cylindrical Fermi surface, which are estimated to be $14%$ and $17%$ of the first Brillouin zone, respectively. The mass of the conduction electrons is $4.1 {m}_{0},$ suggesting the enhancement due to many-body effects. Assuming a parabolic energy band, we obtain a Fermi energy of $\ensuremath{\sim}20 \mathrm{meV}$ and an interlayer transfer integral of $\ensuremath{\sim}1 \mathrm{meV}.$