Superconducting properties and Fermi-surface topology of the quasi-two-dimensional organic superconductor lambda-(BETS)(2)GaCl4 (BETS bis(ethylene-dithio)tetraselenafulvalene)
C. Mielke et al., Superconducting properties and Fermi-surface topology of the quasi-two-dimensional organic superconductor lambda-(BETS)(2)GaCl4 (BETS bis(ethylene-dithio)tetraselenafulvalene), J PHYS-COND, 13(36), 2001, pp. 8325-8345
The Fermi-surface topology of the organic superconductor lambda-(BETS)(2)Ga
Cl4 has been determined using the Shubnikov-de Haas and magnetic breakdown
effects and angle-dependent magnetoresistance oscillations. The former expe
riments were carried out in pulsed fields of up to 60 T, whereas the latter
employed quasistatic fields of up to 30 T. All of these data show that the
Fermi-surface topology of lambda-(BETS)(2)GaCl4 is very similar to that of
he most heavily studied organic superconductor, kappa-(BEDT-TTF)(2)Cu(NCS)
(2), (BEDT-TTF drop bis(ethylene-dithio)tetrathiafulvalene), except in one
important respect: the interplane transfer integral of lambda-(BETS)(2)GaCl
4 is a factor similar to5 larger than that of kappa-(BEDT-TTF)(2)Cu(NCS)(2)
. The increased three-dime,nsionality of k-(BETS)(2)GaCl4 is manifested in
radio-frequency penetration-depth measurements, which show a clear dimensio
nal crossover in the behaviour of H-c2(T). The radio-frequency measurements
have also been used to extract the Labusch parameter determining the fluxo
id interactions as a function of temperature, and to map the flux-lattice m
elting curve.