Survey of the Thermodynamic Properties of the Charge Density Wave Systems

Figure 3

Color on line. Stress dependence derived from Ehrenfest eq. (4) with the thermal expansion coefficient discontinuities (Tables 1 and 2) measured at the CDW phase transitions as a function of T_CDW. along the axis in TbTe₃ at T_CDW1 = 330 K (blue circle) and ErTe₃ at T_CDW2 = 150 K (black circle) deduced from the thermal expansion measurements using X-rays technique reported by Ru et al. [8]. Results with TiSe₂ (violet circle) T_CDW = 200 K [20]; 2H-TaSe₂ (pink down triangle) [25]; NbSe₃ (green circle T_CDW = 145 K) [25]; 2H-NbSe₂ (blue square) [18, 19]; K_0.3MoO₃ (blue up triangle T_CDW = 180 K) [31, 32]; (TaSe₄)₂I (brown diamond) [39]; LaAgSb₂ (red square T_CDW1 = 210 K ) [44]; and Cr (light blue square [54]). Lines and are lineal temperature dependence.