Kondo behavior

Summary. We suggest a simple system of two electron droplets which should display two-channel Kondo behavior at experimentally-accessible temperatures. Stabilization of the two-channel Kondo fixed point requires fine control of the electrochemical potential in each droplet, which can be achieved by adjusting voltages on nearby gate electrodes. We study the conditions for obtaining this type of two-channel Kondo behavior, discuss the experimentally-observable consequences, and explore the generalization to the multi-channel Kondo case.1... 

The heavy fermion antiferromagnet Ce3Pt4lni3 (Tn = 0.95 K) exhibits imusual Kondo behavior (Hundley et al., 2001) and it has an imusually large electronic contribution to the specific heat of about 1 J/molK at the Neel temperature. Thermoelectric power and Hall effect... 

Early work on dilute lanthanide systems was motivated by the vast experimental and theoretical effort that had been expended on understanding dilute magnetic 3d impurities in noble metal hosts. In 1965, Sugawara discovered a resistance minimum in the YCe system, providing the first evidence of Kondo behavior for a lanthanide solute. This led to the discovery of numerous lanthanide Kondo systems which exhibited anomalies in their physical properties qualitatively identical to those found in 3d Kondo systems. 

Fig. 11.12. Reduced specific heat jump ACIACq vs reduced transition temperature TJT for (LaPr)Sn, alloys (solid circles and solid squares McCallum et al., 197Sa) and (LaSmjSn alloys (open circles DeLong et al., 1976). The solid line is derived from numerical calculations based on the theory of Keller and Fulde (1973) for crystal field-split lanthanide impurities in a superconductor. The BCS law of corresponding states behavior (dashed curve) and the AG behavior (dot-dashed curve) are shown for comparison. The negative deviations of the ACIACn vs TJT data from the AG curve are consistent with Kondo behavior (see fig. 11.10) for (I Sm)Sn3 alloys.

The UCu4fiAl8 i system has been obtained in the form of amorphous thin film. From ac resistivity measurements it follows that compared to the results in the crystalline bulk alloys, the onset of magnetic order is suppressed at low Cu concentrations, while the onset of a coherent heavy-fermion state is suppressed at high x. The system reveals a single-ion Kondo behavior down to the lowest temperatures, but significant deviations were detected from the behavior of dipolar Kondo system (Lunkenheimer et al. 1994). 

This indicates a modulated spin structure. The maximum is around 300 T corresponding to a moment of 1.5 /in quite in contrast to the low moment of NpSnj. From high-pressure data it was concluded that NpSuj is a Kondo lattice system. Kondo behavior may also be present in Npln3 as suggested by recent resistivity data (Gal et al. 1992). 

The molar heat capacities Cp of Tmo.2Yo.8Se and YSe between 1.6 and 20 K are shown in Fig. 205a. The magnetic contribution (=difference between Cp of Tmo.2Yo.8Se and YSe) is relatively large above 16 K as demonstrated in Fig. 205 b. It increases with increasing temperature, which is attributed to crystal field effects. A characteristic upturn of Cp below 4 K is related to the observed deviation from Kondo behavior. The variation of the entropy between 2 and 16 K is 0.31 R [mol Tm], Cornut et al. [8]. 

Takahashi, K., Muroya, M., Kondo, K., Hasegawa, T., Kikuchi, I., and Kawakami, M., Post Combustion Behavior in In-Bath Type Smelting Reduction Furnace, AS /./ Ini., 32 102 (1992)... 

This review will include both types of studies, but will not discuss in any detail optically pumped NMR of semiconductors, which has been well-reviewed [5, 11, 12,14], or other unconventional techniques for detection of NMR signals. Physics-related NMR studies of more complicated semiconductor behavior such as Kondo insulators or semiconductors and other unusual semiconducting phases, and semiconducting phases of high-Tc superconductors, while very important in physics, will be neglected here. I have deemed it of some value to provide rather extensive citation of the older as well as of the more recent literature, since many of the key concepts and approaches relevant to current studies (e.g., of nanoparticle semiconductors) can be found in the older, often lesser-known, literature. My overall aim is to provide a necessarily individual perspective on experimental and theoretical approaches to the study of semiconductors by NMR techniques that will prove useful to chemists and other scientists. 

Yoshimura, J., Ebina, Y, Kondo, J., Domen, K., Tanaka, A. 1993. Visible-light induced photocatalytic behavior of a layered perovskite type niobate. J Phys Chem B 97 1970-1973. 

Aliphatic hydrocarbon solutes are primarily solubilized within the hydrocarbon core region of the surfactant micelles. Solubilization isotherms (activity coefLcient versus mole fraction, X) for these hydrophobic solutes exhibit curves that decrease from relatively large values at inLnite dilution to lower values as X increases toward unity (Figure 12.6). The aromatic hydrocarbons are intermediate in behavior between highly polar solutes, which are anchored in the micelle surface region, and aliphatic hydrocarbons, which preferentially solubilize in the hydrocarbon core region (Kondo et al., 1993). 

It is thus reasonable to conclude that the mechanism of the superconductivity in A3C6o is the dynamic Jahn-Teller effect when we consider it in the real space while it is the Moskalenko-Suhl-Kondo mechanism when we consider it in the wavenumber space, as schematically shown in Fig 11. That is, for A C o the superconductivity induced by the dynamic Jahn-Teller effect is equivalent to that induced by the Moskalenko-Suhl-Kondo mechanism. Soon after the discovery of the superconductivity in A3C6o, Rice et al. [23], Asai and Kawaguchi [24], and Kristoffel and Ord [25] pointed out the importance of the Moskalenko-Suhl-Kondo mechanism in the superconductivity of A3C60- This is a remarkable suggestion although, at that time, it was too early to understand a variety of behaviors of AVC60 in a unified way. 

Kondo, Y and Kuboto, M., Precipitation Behavior of Platinum Group Metals from Simulated High Level Liquid Waste in Sequential Denitration Process, J. Nucl. Sci. Technol., 29(2), (1992), ppl40-l48. 

---