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arXiv · 0909.4795

Deconfinement transition and dimensional crossover in the Bechgaard-Fabre salts: pressure- and temperature-dependent optical investigations

A. Pashkin·M. Dressel·M. Hanfland·C. A. Kuntscher
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Abstract

The infrared response of the organic conductor (TMTSF)$_2$PF$_6$ and the Mott insulator (TMTTF)$_2$PF$_6$ are investigated as a function of temperature and pressure and for the polarization parallel and perpendicular to the molecular stacks. By applying external pressure on (TMTTF)$_2$PF$_6$, the Mott gap rapidly diminishes until the deconfinement transition occurs when the gap energy is approximately twice the interchain transfer integral. In its deconfined state (TMTTF)$_2$PF$_6$ exhibits a crossover from a quasi-one-dimensional to a higher-dimensional metal upon reducing the temperature. For (TMTSF)$_2$PF$_6$ this dimensional crossover is observed either with increase in external pressure or with decrease in temperature. We quantitatively determine the dimensional crossover line in the pressure-temperature diagram based on the degree of coherence in the optical response perpendicular to the molecular stacks.

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A. Pashkin, M. Dressel, M. Hanfland, C. A. Kuntscher. 2009-09-25. Deconfinement transition and dimensional crossover in the Bechgaard-Fabre salts: pressure- and temperature-dependent optical investigations. https://doi.org/10.1103/physrevb.81.125109

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