Self-consistent large-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>N</mml:mi></mml:math>expansion for normal-state properties of dilute magnetic alloys

Bickers, N. E.; Cox, D. L.; Wilkins, John W.

doi:10.1103/physrevb.36.2036

Cited by 584 publications

(399 citation statements)

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“…The appearance of the Kondo peak even at 300 K reflects the strong c − f hybridization in YbNi 3 Ga 9 . With decreasing temperature from 300 K, the Kondo peak is shifted toward E F and increases in intensity, which is well described within a framework of the single impurity Anderson model (SIAM) [12]. Similar phenomena have been reported in the valence fluctuating compounds such as YbAgCu 4 [13] and YbCdCu 4 [14].…”

Section: Resultssupporting

confidence: 74%

Photoemission Studies of Kondo Lattice Compounds YbNi₃(Ga₁₋_xAl_x)₉

Utsumi

Sato

Nagata

et al. 2014

Proceedings of the 12th Asia Pacific Physics Conference (APPC12)

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We have investigated the electronic structure of YbNi 3 (Ga 1−x Al x ) 9 (x=0, 0.05, 0.10, 0.15) by means of hard x-ray (hν ∼ 6 keV) and low energy (hν ∼ 7 eV) photoemission spectroscopies (HAXPES and LEPES). Both Yb 2+ and Yb 3+ components are observed in the Yb 3d HAXPES spectra, which is an evidence of the valence fluctuation in YbNi 3 (Ga 1−x Al x ) 9 . A substitution of an Al ion for a Ga ion in YbNi 3 Ga 9 changes the Yb ion into a trivalent state. The LEPES spectra of YbNi 3 Ga 9 clearly exhibit the Kondo peak near the Fermi level (E F ) and the Kondo temperature is estimated to be T K ∼ 550 K. With the Al substitution, the Kondo peak is shifted toward E F , indicating the decrease of T K

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Section: Resultssupporting

confidence: 74%

Photoemission Studies of Kondo Lattice Compounds YbNi₃(Ga₁₋_xAl_x)₉

Utsumi

Sato

Nagata

et al. 2014

Proceedings of the 12th Asia Pacific Physics Conference (APPC12)

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“…In a number of HF compounds the Kondo effect manifests itself as a maximum in S͑T͒ in the vicinity of the T K . [32][33][34] In a similar way the resistivity curve of YbAgGe displays a characteristic behavior in which the resistivity decreases rapidly below ϳ100 K expected due to the CEF effect and shows a hump below 25 K related to the development of coherent quasi-particles. 18 We therefore assume that T max in TEP measurements represents the crossover temperature ͑T K ͒ from local moment to HF behavior.…”

Section: Discussionmentioning

confidence: 73%

Thermoelectric power investigations of YbAgGe across the quantum critical point

2010

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The magnetic field and temperature dependences of the thermoelectric power (TEP) of the antiferromagnetically ordered heavy fermion compound YbAgGe are measured across the field-induced quantum critical point. These TEP measurements reproduce the earlier H-T phase diagram and identify an additional domelike phase between ∼45and ∼70 kOe. On the low-field side of this region, H>Hc∼45 kOe, the sign of the TEP changes from negative to positive; on the high-field side of this region, H≈70 kOe, a nonFermi-liquid state is evidenced as the logarithmic temperature dependence of S(T)/T, in agreement with previous specific heat results C(T)/T∝−log(T). For higher fields, H>70 kOe, the observed large value of α, S(T)=αT, is indicative of the heavy fermion state and shows a correlation with C(T)/T. Keywords Physics and Astronomy Disciplines Condensed Matter Physics CommentsThis article is from Physical Review B 82 (2010) The magnetic field and temperature dependences of the thermoelectric power ͑TEP͒ of the antiferromagnetically ordered heavy fermion compound YbAgGe are measured across the field-induced quantum critical point. These TEP measurements reproduce the earlier H-T phase diagram and identify an additional domelike phase between ϳ45 and ϳ70 kOe. On the low-field side of this region, H Ͼ H c ϳ 45 kOe, the sign of the TEP changes from negative to positive; on the high-field side of this region, H Ϸ 70 kOe, a non-Fermi-liquid state is evidenced as the logarithmic temperature dependence of S͑T͒ / T, in agreement with previous specific heat results C͑T͒ / T ϰ −log͑T͒. For higher fields, H Ͼ 70 kOe, the observed large value of ␣, S͑T͒ = ␣T, is indicative of the heavy fermion state and shows a correlation with C͑T͒ / T.

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“…The complete setup of nonstandard direct perturbation theory is well documented, including the diagrammatic rules for the processes to be discussed in the following [3,8,31]. concentrated on the limit U = ∞ of infinite local Coulomb repulsion and were termed NCA [8,9,32]. They were based on the leading skeletons of order V 2 to the ionic self energies Σ 0 (z) and Σ 1σ (z) and furnished a qualitatively correct picture e.g.…”

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confidence: 99%

Conserving approximations in direct perturbation theory: new semianalytical impurity solvers and their application to general lattice problems

Grewe¹,

Schmitt²,

Jabben³

et al. 2008

J. Phys.: Condens. Matter

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Abstract. For the treatment of interacting electrons in crystal lattices approximations based on the picture of effective sites, coupled in a self-consistent fashion, have proven very useful. Particularly in the presence of strong local correlations, a local approach to the problem, combining a powerful method for the short ranged interactions with the lattice propagation part of the dynamics, determines the quality of results to a large extent. For a considerable time the non crossing approximation (NCA) in direct perturbation theory, an approach originally developed by Keiter for the Anderson impurity model, built a standard for the description of the local dynamics of interacting electrons. In the last couple of years exact methods like the numerical renormalization group (NRG) as pioneered by Wilson, have surpassed this approximation as regarding the description of the low energy regime. We present an improved approximation level of direct perturbation theory for finite Coulomb repulsion U , the crossing approximation one (CA1) and discuss its connections with other generalizations of NCA. CA1 incorporates all processes up to fourth order in the hybridization strength V in a self-consistent skeleton expansion, retaining the full energy dependence of the vertex functions. We reconstruct the local approach to the lattice problem from the point of view of cumulant perturbation theory in a very general way and discuss the proper use of impurity solvers for this purpose. Their reliability can be tested in applications to e.g. the Hubbard model and the Anderson-lattice model. We point out shortcomings of existing impurity solvers and improvements gained with CA1 in this context. This paper is dedicated to the memory of Hellmut Keiter.

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Self-consistent large-Nexpansion for normal-state properties of dilute magnetic alloys

Cited by 584 publications

References 84 publications

Photoemission Studies of Kondo Lattice Compounds YbNi₃(Ga₁₋_xAl_x)₉

Photoemission Studies of Kondo Lattice Compounds YbNi₃(Ga₁₋_xAl_x)₉

Thermoelectric power investigations of YbAgGe across the quantum critical point

Conserving approximations in direct perturbation theory: new semianalytical impurity solvers and their application to general lattice problems

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Self-consistent large-Nexpansion for normal-state properties of dilute magnetic alloys

Cited by 584 publications

References 84 publications

Photoemission Studies of Kondo Lattice Compounds YbNi3(Ga1−xAlx)9

Photoemission Studies of Kondo Lattice Compounds YbNi3(Ga1−xAlx)9

Thermoelectric power investigations of YbAgGe across the quantum critical point

Conserving approximations in direct perturbation theory: new semianalytical impurity solvers and their application to general lattice problems

Contact Info

Product

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Photoemission Studies of Kondo Lattice Compounds YbNi₃(Ga₁₋_xAl_x)₉

Photoemission Studies of Kondo Lattice Compounds YbNi₃(Ga₁₋_xAl_x)₉