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The temperature dependences of the electric-transport properties of the two-dimensional organic conductors beta-(BEDT-TTF)2SF5CH2CF2SO3, beta-(d8-BEDT-TTF)2SF5CH2CF2SO3, and beta-(BEDT-TTF)2SF5CHFSO3 are measured by dc methods in and perpendicular to the highly-conducting plane. Microwave measurements are performed at 24 and 33.5 GHz to probe the high-frequency behavior from room temperature down to 2 K. Superconductivity is observed in beta-(BEDT-TTF)2SF5CH2CF2SO3 and its deuterated analogue. Although all the compounds remain metallic down to low-temperatures, they are close to a charge-order transition. This leads to deviations from a simple Drude behavior of the optical conductivity which become obvious already in the microwave range. In beta-(BEDT-TTF)2SF5CH2CF2SO3, for instance, charge fluctuations cause an increase in microwave resistivity for T < 20 K which is not detected in dc measurements. beta-(BEDT-TTF)2SF5CHFSO3 exhibits a simple metallic behavior at all frequencies. In the dc transport, however, we observe indications of localization in the perpendicular direction.
To elucidate the pressure evolution of the electronic structure in an antiferromagnetic dimer-Mott (DM) insulator ${beta}^{prime}$-(BEDT-TTF)$_2$ICl$_2$, which exhibits superconductivity at 14.2 K under 8 GPa, we measured the polarized infrared (IR)
The dielectric constant and ac conductivity have been measured for the layered organic conductor theta-(BEDT-TTF)_2CsZn(SCN)_4 along the out-of-plane direction, which show a relaxation behavior similar to those in the charge-density-wave conductor. M
The low-temperature charge-density-wave (CDW) state in the layered organic metals $alpha $-(BEDT-TTF)$_2$MHg(SCN)$_4$ has been studied by means of the Shubnikov -- de Haas and de Haas -- van Alphen effects. In addition to the dominant alpha-frequency
We show that Shubnikov-de Haas oscillations in the interlayer resistivity of the organic superconductor $beta$-(BEDT-TTF)$_{2}$SF$_{5}$ CH$_{2}$CF$_{2}$SO$_{3}$ become very pronounced in magnetic fields $sim$~60~T. The conductivity minima exhibit the
The effects of electron correlation in the quasi-two-dimensional organic conductor alpha-(BEDT-TTF)2I3 are investigated theoretically by using an extended Hubbard model with on-site and nearest-neighbor Coulomb interactions. A variational Monte Carlo