Phase diagram TMTSF

Fig. 13 Generalized phase diagram for the (TMTSF)2X and (TMTTF)2X by Jerome [195]. CL, SP, SDW, and SC refer to charge-localized (which corresponds to charge-ordered state), sprn-Peierls, spin density wave, and superconducting states, respectively, (a) (TlVrrTF)2PF6, (b) (TMTTF>2Br, (c) (TMTSF)2PF6, (d) (TMTSF)2C104...

Figure 12.6 shows what is understood about the temperature-pressure phase diagram of several TMTSF salts. 

Temperature-pressure phase diagram of TMTSF and TMTTF salts [30]. 

Figure 44 Quantized Hall voltage of (TMTSF)2PF6 and phase diagram. The integers indicate the number of filled Landau levels in each subphase. (After Ref. 127.)...

Figure 45 Quantized Hall voltage in (TMTSF)2C104 (two samples) (after Ref. 130) and phase diagram (from Ref. 132). A new phase line has been discovered around 1 K and 30 T (after R. C. Yu et al, Phys. Rev. Lett, 65 2458 (1990)). The phase that extends from 8 to 27 T is presumably N = 1 [130].

Fig. 20. Illustration of the temperature-pressure phase diagram for (TMTSF)2X salts. The critical pressure Pc varies between ambient pressure and 12 kbar for different compounds.

Only in the case of the 2 1 Re04 " salt, and of course X = I3 and IBr2 , do the properties of the (ET)2X salts resemble the (TMTSF)2X series (S). With a critical pressure of 4-6 kbar, the Re04" salt fits the phase diagram in Fig. 20. The great similarity in properties of salts based on different molecules suggests that the solid-state environment is as crucial to the physical behavior as are the molecular characteristics. 

Pig. 2.8. (a) Phase diagram of the field-induced spin density wave (FISDW) states predicted by the standard model. The dashed line indicates the experimentally supposed reentrance in (TMTSF)2C104. (b) Phase diagram of (TMTSF)2PFe obtained from Hall effect and magnetoresistance measurements at approximately 6kbar. Prom [79]... 

Fig- 2,9. Experimentally determined pressure-field-temperature phase diagrams for (a) (TMTSF)2PF6 and (b) (TMTSF)2C104. From [89]... 

When magnitude of the electron-electron Coulomb interaction increases, the system is expected to show a ehange from the SDW dominated state to the spin-Peierls one. This was verified in another system, (TMTTF(tetramethyltetra-thiafulvalene))2X and (TMTSF)2X [74]. The former materials have the narrower band width than the latter. This means that the role of Coulomb interaction is more important in the former system than in the latter. The former system is expected to have the spin-Peierls state and the latter one the SDW state. Systematic studies have proposed the phase diagram shown in Fig. 23 [74]. 

Figure 23 Schematic phase diagram of the (TMTTF, TMTSF)2X system. (Reproduced from D. Jerome, Organic Conductors, Ed. J-P. Farge (Marcel Dekker, 1994) p. 420, Fig.

TMTCF denotes TMTTF or TMTSF molecule. The amount of charge transfer in this family with one-dimensional structures is such TMTCF " and X . The band structure and the Fermi surface are open as shown in Fig. 29 for the case of (TMTTF)2X [94]. The phase diagram of this family on the plane of pressure (p) and temperature (7) is shown in Fig. 30 proposed by Jerome [95]. The major... 

Fig. 10.5 (TMTSF)2PF6 a phase diagram for the transition temperature as a function of the applied pressure. The data points are due to different authors. At low temperatures and low applied pressures, one observes the behaviour of an insulator with spin-density waves. At low temperature and high pressure, the substance is superconducting at higher temperature it is metallic. Crystallographic data triclinic, a = 7.29 A, b = 7J A,c= 13.52 A, = 83.39°, = 86.27°,... 

Fig. 13. Phase diagram for (TMTSF)2PF6, redrawn from Ref. [11].

The temperature dependence of resistivities of five typical DMET salts is shown in Fig. 1 [8]. Among them, three show superconductivity. (DMET)2Au(CN)2 shows a resistivity upturn at 28 K at ambient pressure, and needs some pressure to become a superconductor [2]. The insulating phase is SDW [9,10] and the T-P phase diagram (Fig. 2) [11] is similar to that of the (TMTSF)2X salts. However, the pressure range, where both superconductivity and... 

Fig. 1. Phase diagram of the slowly cooled (TMTSF)2C104. Cross and plus symbols represent calorimetric data. The dots represent magnetization data. Arrows indicate the partial reentrances of the metal into the FISDW.

Figures 3 and 4 illustrate for the (TMTSF)2C104 compound, the two main effects of the cooling rate. The first effect concerns the shift of the threshold field, as displayed on Fig. 3 the threshold fields corresponding to quenched and relaxed states are represented by solid and dashed arrows, respectively. This shift is responsible for the discrepancy we observed between the threshold fields, as determined by specific heat or by magnetocaloric effect measurements 31,32 fact. Figure 3 leads to a first conclusion in order to construct a coherent phase diagram, all the experiments are to be performed for the same cooling rate, at...

A generalized T-P phase diagram, which includes not only the TMTSF system but also TMTTF ID metals and insulators, describing the variety of ground states (spin-Peierls, SDW, and SC states), has been proposed. 

Figure 3.13. Phase diagram T,P,x) for different ground states found experimentally in [(TMTTF)jc (TMTSF), 42(C104) alloys [333].

Figure 3.23. Magnetic phase diagram of (TMTSF)2Tap6. indicates the spin-flop magnetic field in the AF state).

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