Specific heat in quasi-one-dimensional conductors K0.3MoO3 and (TMTTF)2AsF6

We measured the specific heat cp(T) of single crystals of quasi-one-dimensional conductors K0.3MoO3 and (TMTTF)2AsF6 by differential thermal analysis (DTA) method. In K0.3MoO3, a clear discontinuous change Δcp0∼1.2 J/mol/K was detected at the charge density wave (CDW) transition temperature TCDW=180 K. On the other hand, in (TMTTF)2AsF6, cp(T) showed a weak anomaly at the charge order (CO) transition temperature TCO=100 K. The entropy lost at around TCO was ΔS ∼0.24 J/mol/K at most, that is much smaller than R ln 2∼5.8 J/mol/K, which is the expected magnitude in the case of order-disorder transition. The CO of (TMTTF)2AsF6 might be related to the displacive type ferroelectric.