Fermi liquid behavior

It is worth remarking that the above phenomenology leads one to conclude that the marginal Fermi liquid behavior hypothesized for the optimally doped samples (x 0.16) does not reflect quantum critical behavior. 

Below the crossover, both channels are decoupled. A Fermi-liquid behavior is recovered using renormalized values of the interactions at the crossover temperature. We may expect mean-field treatments for dimensionality 2 or 3 to become valid at T critical exponents for the SDW instability in (TMTSF)2PF6 (see Section III.B). 

The quasiplateau for Tf1 which is observed for C104 and also for PF6 salts under pressure (Fig. 10b) is therefore related to 2kF correlations in a transient temperature regime when the nesting vector evolves from a purely one-dimensional situation (2fcF,0) to a vector that provides the best nesting of the two (three)-dimensional Fermi surface. Below the crossover temperature Tx a Fermi liquid behavior is recovered with an enhanced Korringa... 

TMTSF)2PF6 under 9 kbar, suggesting a recovery of the usual Fermi liquid behavior (Fig. 16). 

Transport. (TMTTF)2X. Deviations to the Fermi liquid behavior are particularly revealing for (TMTTF)2X compounds for which there is a loss of the metallic character at a characteristic temperature that can be in magnitude far above the critical temperature domain under low pressure conditions (Fig. 4). The scale... 

As the temperature is decreased below T, , the anisotropy ratio remains temperature dependent, a feature that can hardly be tied with a Fermi liquid picture. It is only below 10 K in (TMTSF)2PF5 under 9 kbar that the ratio becomes constant in temperature suggesting a recovery of the usual Fermi liquid behavior (Fig. 16). 

The review of HF compounds is divided into three subsections (Ce-, U- and other materials). At the end of each paragraph dealing with a certain compound or series of compounds we give a short summary of the main impact of pSR data. Compounds where magnetic instability leads to non-Fermi-liquid behavior are discussed in the following extra section. 

The pressiue dependence of the electrical resistivity of YbCuAl was investigated (Alami-Yadri et al. 1998, 1999a,b) up to 8 GPa. The resistivity at 300 K decreases with increasing pressure. At 8 GPa a dependence occurs at low temperature (Fermi-liquid behavior), and the Kondo temperature decreases with increasing pressure. The experimental setup for these measurements was presented by Jaccard et al. (1998). Furthermore, point-contact spectroscopy was used to measure the interconfigurational excitation energies and conduction-electron lifetime width of valence-fluctuating YbCuAl (Bussian et al. 1982). 

D. E. MacLaughlin, Magnetic Resonance, Non-Fermi-Liquid Behavior, and Disorder in f-Electron Materials , /. Phys. Chem. Solids, 2007, 68, 2024. 

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