Kondo screening

ZO200 Kiuchi, F., M. Hioki, N. Nakamura, N. Miyashita, Y. Tsuda, and K. Kondo. Screening of crude drugs used in Sri Lanka for nematocidal activity on the larva of Toxocaria canis. Shoyakugaku Zasshi 1989 43(3) 288-293. 

Quasiparticle formation and Kondo screening in the periodic Anderson model... 

The thermodynamics of the system, especially the local susceptibility, allows the study of the Kondo screening and identifies the relevant energy scales. The Kondo scales are obtained by extrapolating Ximp( —>0) = I/Tq, where Ximp( is the additional local susceptibility due to the introduction of the effective impurity into a host of d electrons. As shown in fig. 6, at the symmetric limit (/if =/id = 1) the Kondo scale for the PAM To is strongly enhanced compared to Tq , the Kondo scale for a SIM with tiie same model parameters. This behavior has been observed before (Rice and Ueda 1986, Jarrell... 

Perhaps the most unusual feature of the band dispersion shown in fig. 12 is the presence of a weakly-dispersive f quasiparticle band as much as 0.3above the Fermi energy. The quasiparticle bands which form due to Kondo screening are expected to lie within about Tq of the Fermi surface (Martin and Allen 1979). The presence of a screening band this far Irom the Fermi surface would seem to correspond to a significantly larger f-d hybridization than that which is required to form a small Kondo scale Tq. To study this apparent inconsistency one introduces an effective hybridization strength r((o). 

Fig. 14. Mapping to Nozieres single-band Hubbard state. In the PAM (top) f-orbitals are represented by shaded rectangles, d-orbitals by shaded circles, electrons by small shaded circles pierced by up and down pointing arrows, and the Kondo singlet is represented by a thick wavy line. Only the conduction electrons with energies within kgTf of the Fermi surface can participate in Kondo screening of the moments. Thus, only a fraction of the moments may be screened by the conventional Kondo effect. The screened and...

Iwata S, Sukegawa K, Sasaki T, Kokuryu M, Yamasita S, Noma A, Iwasa S, Kondo N, Orii T (1997) Mass screening test for mucopolysaccharidoses using the 1,9-dimethylene blue method positive interference from paper diapers. Clin Chim Acta 264 245-250... 

Harada, K., Murata, H., Qiang, Z., Suzuki, M., and Kondo, F. 1996a Mass spectrometric screening method for microcystins in cyanobacteria. Toxicon 34 701—710. 

Kondo (1964, 1969) showed that the behavior of a single magnetic impinity in a nonmagnetic metallic host at low temperatures cannot be understood in terms of the electronic states of the impurity ion alone, but must be treated as a many body phenomenon. Around the inqiurity a screening cloud of spin-polarized ce develops when... 

Kondo, M., Nichihara, T., Shimamoto, T., Watabe, K. and Fujii, M. (1988) Screening test method for degradation of chemicals in water. A simple and rapid method for biodegradation test. Eisei Kagaku, 34, 115-22. 

Boron-doped diamond (BDD) is known to be an interest electrode material for sensitive electroanalysis due to its wide potential window and low background current. Kondo et fabricated a screen-printed... 

The next important experimental discovery was the observation of the two-peak structure in Pr and Nd compounds by Parks et al. (1984) and Wieliczka et al. (1984b). Basically, one sees a similar spectrum as seen in a cerium compound, but displaced further below Ep (1 eV in the case of Pr and 3eV in the case of Nd) with the peak separation remaining about the same. This observation lead Parks et al. (1984) to conclude that a Kondo interpretation of the peak near Ep is incorrect (such a resonance would be tied to Ep). In fact, the spectrum is most easily interpreted from the screening model point of view (see Norman et al. (1985b) and Hiifher (1986)). Modifications of the G-S model, however, seem to account for at least the Pr case (Gunnarsson and Schonhammer 1985). 

The motion of a heavy particle when accompanied by a screening cloud of band electrons was first studied by Kondo (1984) and later by Kagan and Prokofev (1986) as a model for muon diffusion in metals. Liu (1987) and Kagan and Prokofev (1987) independently proposed that the same mechanism applies in heavy-fermion systems. The idea is that the f band is formed by the hopping of an f hole whose motion is accompanied by the screening cloud. Just like the band problem in the spin fluctuation resonance model, the hopping is the result of the hybridization interaction. Consequently, the dispersion of the f band is again solved from eq. (52) where Gf(to) is now calculated from the f hole spectrum in eq. (57) (Liu 1987, 1988) ... 

The evolution of theoretical models has been driven by experiment. To date, the f component of the one-electron addition/removal spectra of alloys containing Ce ions, as well as ordered Ce compounds, are qualitatively similar. Due to the difficulty of separating out the f component of the spectrum, the only concentration dependence that has been identified is the linear dependence of the overall intensity. This unsatisfactory state of affairs has caused theorists to focus their attention primarily on single-impmity models that have the same qualitative features as observed in experiments. Thereby, effects that are present in ordered compotmds have been, hitherto, largely ignored. We shall categorize these theories into two classes, namely Kondo models and screening models. 

As outlined above, the physics associated with the Kondo model can be ascribed to the local moment inducing a compensating spin polarization cloud in the gas of conduction electrons, at low temperatures. The models considered in the next section are categorized as screening models, in which considerations of electrical charge neutrality in the unit cell are brought into play. 

The PAM is studied in the high-dimensional limit mentioned in sect. 4. Since the Kondo effect is independent of lattice dimensionality, working in this limit will not inhibit the study of screening in the lattice. The PAM Hamiltonian on a Ds-dimensional hypercubic lattice is... 

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