Prof Arzhang Ardavan

Abstract:

Thermally activated conductivity at integer Landau-level filling factors in the Q2D organic metal β″-(BEDT-TTF)2SF5CH2CF2SO 3 was observed for the first time. The activation energies deduced from the conductivity showed good agreement with the Landau-level spacings once broadening is taken into consideration.

Abstract:

We show that Shubnikov-de Haas oscillations in the interlayer resistivity of the organic superconductor beta(")-(BEDT-TTF)2SF5CH2CF2SO3 become very pronounced in magnetic fields approximately 60 T. The conductivity minima exhibit thermally activated behavior that can be explained simply by the presence of a Landau gap, with the quasi-one-dimensional Fermi surface sheets contributing negligibly to the conductivity. This observation, together with complete suppression of chemical potential oscillations, is consistent with an incommensurate nesting instability of the quasi-one-dimensional sheets.