Bethe ansatz and 1/N expansion results for N-fold degenerate magnetic impurity models

Rasul, J.W.; Hewson, A. C.

doi:10.1088/0022-3719/17/14/013

Cited by 56 publications

(13 citation statements)

References 28 publications

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“…We can then infer a value of T K by using T K ϭ (RlnN)/␥ (22) or by using T K ϭ (N Ϫ 1) 2 Rw N /3N␥ (where w N is a multiplicative factor that is a function of N as discussed in ref. 21). These expressions produce T K values that are within 5% of each other for 2 Յ N Յ 8.…”

Section: Discussionmentioning

confidence: 99%

Six closely related YbT ₂ Zn ₂₀ (T = Fe, Co, Ru, Rh, Os, Ir) heavy fermion compounds with large local moment degeneracy

Torikachvili

Jia

Mun

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

243

187

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Heavy fermion compounds represent one of the most strongly correlated forms of electronic matter and give rise to low temperature states that range from small moment ordering to exotic superconductivity, both of which are often in close proximity to quantum critical points. These strong electronic correlations are associated with the transfer of entropy from the local moment degrees of freedom to the conduction electrons, and, as such, are intimately related to the low temperature degeneracy of the (originally) moment bearing ion. Here we report the discovery of six closely related Yb-based heavy fermion compounds, YbT 2Zn20, that are members of the larger family of dilute rare earth bearing compounds: RT 2Zn20 (T ‫؍‬ Fe, Co, Ru, Rh, Os, Ir). This discovery doubles the total number of Yb-based heavy fermion materials. Given these compounds' dilute nature, systematic changes in T only weakly perturb the Yb site and allow for insight into the effects of degeneracy on the thermodynamic and transport properties of these model correlated electron systems. correlated electron ͉ intermetallic compound H eavy fermion compounds have been recognized as one of the premier examples of strongly correlated electron behavior for several decades. Ce-and U-based heavy fermion compounds have been well studied, and in recent years a small number of Yb-based heavy fermions have been identified as well (1-3). Unfortunately, in part due to the somewhat unpredictable nature of 4f ion hybridization with the conduction electrons, it has been difficult to find closely related (e.g., structurally) heavy fermion compounds, other than of the ThCr 2 Si 2 structure, especially Yb-based ones, that allow for systematic studies of the Yb ion degeneracy. Part of this difficulty is associated with the fact that the 4f hybridization depends so strongly on the local environment of the rare earth ion.Dilute, rare earth (R) bearing, intermetallic compounds are ordered materials with Ͻ5 atomic percent rare earth fully occupying a unique crystallographic site. Such materials offer the possibility of investigating the interaction between conduction electrons and 4f electrons in fully ordered compounds for relatively low concentrations of rare earths. For the case of R ϭ Yb or Ce, these materials offer the possibility of preserving low temperature, coherent effects while more closely approximating the single ion Kondo impurity limit. A very promising example of such compounds is derived from the family of RT 2 Zn 20 (4) (T ϭ transition metal), which has recently been shown to allow for the tuning of the nonmagnetic R ϭ Y and Lu members to exceedingly close to the Stoner limit as well as allowing for the study of the effects of such a highly polarizable background on local moment magnetic ordering for R ϭ Gd (5). DiscoveryHere, we present thermodynamic and transport data on six strongly correlated Yb-based intermetallic compounds found in the RT 2 Zn 20 family for T ϭ Fe, Co, Ru, Rh, Os, and Ir, effectively doubling the number of known Yb-based heavy fermi...

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Section: Discussionmentioning

confidence: 99%

Six closely related YbT ₂ Zn ₂₀ (T = Fe, Co, Ru, Rh, Os, Ir) heavy fermion compounds with large local moment degeneracy

Torikachvili

Jia

Mun

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

243

187

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“…The low temperature part of the specific heat data can be well fit by assuming that a quadruplet is Kondo screened and that there is a doublet CEF As the degeneracies of the Yb ions were inferred, by the analysis above, when they enter the Kondo screening states (see Table 9.1), the values of their T K can be then inferred by using T K = (R ln N )/γ, a rough estimation from magnetic entropy [Fisk et al, 1988], or by using T K = (N − 1)π 2 Rω N /3Nγ, the Bethe ansatz results of N-fold CoqblinSchrieffer model [Hewson, 1993] where ω N is the so called Wilson number and that is a function of N as discussed in ref. [Rasul and Hewson, 1984]. These expressions produce T K values that are within 5% of each other for 2 ≤ N ≤ 8.…”

Section: Discussionmentioning

confidence: 75%

“…where ω N is Wilson number [Rasul and Hewson, 1984]. The broad peak appearing in the temperature dependent susceptibility [2.11 (a)] is usually called as 'Kondo peak' and observed in many heavy Fermion systems.…”

Section: Kadowaki-woods Ratiomentioning

confidence: 99%

Magnetic properties of RT2Zn20 R = rare earth, T = Fe, Co , Ru, Rh , Os and Ir

Jia¹

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“…where w N is the generalization of the Wilson number, given by w N = e 1+C−3/2N /2πΓ N (1 + 1/N ) [Rasul, 1984]. The electronic specific heat coefficient, γ, deduced from the thermodynamic equations in the Coqblin-Schrieffer limit [Coqblin, 1969] is given by…”

Section: Wilson Ratio -mentioning

confidence: 99%

“…where γ is expressed using high temperature limit of T K , as defined by Wilson [Rasul, 1984], and this equation is equivalent to Eq. 3.14.…”

Section: Wilson Ratio -mentioning

confidence: 99%

Yb-based heavy fermion compounds and field tuned quantum chemistry

Mun

2010

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Bethe ansatz and 1/N expansion results for N-fold degenerate magnetic impurity models

Cited by 56 publications

References 28 publications

Six closely related YbT ₂ Zn ₂₀ (T = Fe, Co, Ru, Rh, Os, Ir) heavy fermion compounds with large local moment degeneracy

Six closely related YbT ₂ Zn ₂₀ (T = Fe, Co, Ru, Rh, Os, Ir) heavy fermion compounds with large local moment degeneracy

Magnetic properties of RT2Zn20 R = rare earth, T = Fe, Co , Ru, Rh , Os and Ir

Yb-based heavy fermion compounds and field tuned quantum chemistry

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Bethe ansatz and 1/N expansion results for N-fold degenerate magnetic impurity models

Cited by 56 publications

References 28 publications

Six closely related YbT 2 Zn 20 (T = Fe, Co, Ru, Rh, Os, Ir) heavy fermion compounds with large local moment degeneracy

Six closely related YbT 2 Zn 20 (T = Fe, Co, Ru, Rh, Os, Ir) heavy fermion compounds with large local moment degeneracy

Magnetic properties of RT2Zn20 R = rare earth, T = Fe, Co , Ru, Rh , Os and Ir

Yb-based heavy fermion compounds and field tuned quantum chemistry

Contact Info

Product

Resources

About

Six closely related YbT ₂ Zn ₂₀ (T = Fe, Co, Ru, Rh, Os, Ir) heavy fermion compounds with large local moment degeneracy

Six closely related YbT ₂ Zn ₂₀ (T = Fe, Co, Ru, Rh, Os, Ir) heavy fermion compounds with large local moment degeneracy