Fermi surface studies in the magnetic-field-induced superconductorλ−(BETS)2FeCl4

Measurements of the Shubnikov–de Haas (SdH) and angular-dependent magnetoresistance oscillations were performed to study the Fermi surface for a magnetic-field-induced superconductor $\lambda -(\mathrm{BETS}{)}_2{\mathrm{FeCl}}_4.$ 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 $4.1\hspace{0.5em}{m}_0,$ suggesting the enhancement due to many-body effects. Assuming a parabolic energy band, we obtain a Fermi energy of $\sim 20\hspace{0.5em}\mathrm{meV}$ and an interlayer transfer integral of $\sim 1\hspace{0.5em}\mathrm{meV}.$