Survey of the Thermodynamic Properties of the Charge Density Wave Systems

Table 3

Materials (1D CDW), quasi-one-dimensional conductors K_0.3MoO₃, NbSe₃, (TaSe₄)₂I, and TTF-TCNQ. Molar volumes are given in cm³, specific heat discontinuities in J/molK, thermal expansion discontinuities in K⁻¹, elastic velocity discontinuities in , and measured and calculated elastic constants in GPa and ratios.

Materials	Molar volume; cm^3	TCDW; (K)	Specific heat; J/molK	Thermal expansion; coefficient; (K^−1)	Elastic velocity decrease	Elastic constant; GPa	calculated; GPa	Ratio; calculated; /measured
K0.3MoO3	36.3	180	3.6 [30]; 2; [34]	axis; 7x10^−6 [31]	axis; -0.02 [31]	axis; Young modulus; 250 [31]; 60 [33]	250 [31]	~1; ~4
(TaSe4)2I	180	260	0.83 [40]	axis; -1x10^−6 [38]	axis; -0.001 [37]	C33=115 [37]	37	~0.3
NbSe3	40.8	145; 58	3 [26]; 0.4; [26]	in plane; -2x10^−6 [25]	-0.0003; [27]	550; [27]	70	~0.1
TTF-TCNQ	250	55	2.5; [35]	No discontinuity [36]	axis; -0.01 [37]; ~0 [36]	Young modulus E~60 [37]; E~15 [36]