The Role of Librations in TTF-TCNQ
The temperature dependence of the resistivity of TTF-TCNQ has been a mystery for a long time, and received considerable attention since Heeger’s talk in SanDiego early in 1973. The resistivity follows approximately a T2 law ρ11(T,P) = A + B(P) T2 in the temperature region 60 – 300 K. Above 200 K, at ambient pressure, ρ11 is slightly larger, and a fit to T2.3 would be better; also, close to the transition at 52.5 K, up to about 60 K, there are slight upward deviations. However, by and large, this T2 law is followed, and the pressure variation of B is very large. B(P) falls by about a factor of 2 at 4 kbar.1
KeywordsGolden Rule Molecular Plane Large Thermal Expansion Molecular Organic Crystal Anharmonic Force
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