Oscillations, Waves, and Interactions - GWDG

Charge order in one-dimensional solids 323
Conductivity σ (T) / σ (300 K)
10 0
10 −1
10 −2
α-(BEDT-TTF) 2I 3
10−5 10−4 10−3 600 GHz
100 GHz
60 GHz
35 GHz
24 GHz
12 GHz
10 GHz
0 50 100 150 200
dc
250 300
Temperature (K)
Figure 12. Temperature dependent conductivity of α-(BEDT-TTF)2I3 within the highly
conducting plane measured by dc and microwave technique. The charge-order transition at
135 K leads to a rapid drop of the conductivity. The plateau in the conductivity between
40 K and 100 K increases with frequency indicating hopping conduction (after Ref. [23]).
Figure 13. Temperature dependence of the dc resistivity of several Fabre and Bechgaard
salts. As the temperature is reduced, the charges become increasingly localized in
(TMTSF)2AsF6 and (TMTSF)2PF6, before the charge-ordered state is entered below 100 K.
(TMTSF)2SbF6 shows a transition from a metal-like state directly into the charge-ordered
state at TCO = 150 K. (TMTSF)2PF6 undergoes a SDW transition at TSDW = 12 K. Only
(TMTSF)2ClO4 remains metallic all the way down to approximately 1.2 K where it becomes
superconducting (after Ref. [25]).