Low-energy scale of the periodic Anderson model

Pruschke, Thomas; Bulla, Ralf; Jarrell, Mark

doi:10.1103/physrevb.61.12799

Cited by 135 publications

(129 citation statements)

References 51 publications

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“…In CeNi 2−δ As 2 , pressure also appears to reduce the low carrier density even further, as witnessed by an overall increase in ρ xx ðT, pÞ and the variation in ρ yx ðB, pÞ, and this counters the tendency for stronger hybridization by decreasing the Kondo-impurity temperature scale and, even more dramatically, the Kondo-lattice temperature scale below which a heavy Fermi liquid develops (23). A result of this protracted Kondo screening, which is related to the Nozières exhaustion idea that insufficient conduction states are available to screen all of the moments in a Kondo lattice (24), is the stabilization of RKKY-driven AFM order (23), which could include a change in ordering wave vector and provide a reasonable interpretation of the origin of a bump in T N ðpÞ and B c ðpÞ lines near 1.37 GPa. This concept of protracted screening also provides an appropriate explanation for the deviation of T up ðpÞ from an extrapolation above 2.02 GPa.…”

Section: Discussionmentioning

confidence: 99%

Pressure-tuned quantum criticality in the antiferromagnetic Kondo semimetal CeNi _{2−
δ} As ₂

Luo

Ronning

Wakeham

et al. 2015

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

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The easily tuned balance among competing interactions in Kondolattice metals allows access to a zero-temperature, continuous transition between magnetically ordered and disordered phases, a quantum-critical point (QCP). Indeed, these highly correlated electron materials are prototypes for discovering and exploring quantumcritical states. Theoretical models proposed to account for the strange thermodynamic and electrical transport properties that emerge around the QCP of a Kondo lattice assume the presence of an indefinitely large number of itinerant charge carriers. Here, we report a systematic transport and thermodynamic investigation of the Kondo-lattice system CeNi 2−δ As 2 (δ ≈ 0.28) as its antiferromagnetic order is tuned by pressure and magnetic field to zero-temperature boundaries. These experiments show that the very small but finite carrier density of ∼ 0.032 e − /formular unit in CeNi 2−δ As 2 leads to unexpected transport signatures of quantum criticality and the delayed development of a fully coherent Kondo-lattice state with decreasing temperature. The small carrier density and associated semimetallicity of this Kondo-lattice material favor an unconventional, localmoment type of quantum criticality and raises the specter of the Nozières exhaustion idea that an insufficient number of conduction-electron spins to separately screen local moments requires collective Kondo screening.Kondo effect | quantum criticality | heavy Fermion | Nozières exhaustion | anomalous Hall effect D uring the past decade or so, particular interest in Kondolattice systems has focused on those in which a moderate hybridization (J fc ) between magnetic f electrons and a sea of itinerant charge carriers allows their tuning by a nonthermal control parameter to a quantum-critical point (QCP) where nonFermi-liquid (NFL) signatures appear in transport and thermodynamic properties (1). Although several models of quantum criticality have been proposed to account for various NFL properties (2, 3), a common assumption of these models is that the material is metallic. In these metals, the magnetic order that is tuned toward zero temperature is either of a local-moment type derived from Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions when J fc is relatively weak or a spin-density-wave (SDW) instability of a large Fermi surface to which the delocalized 4f state contributes when J fc is stronger. An interesting question is what might be expected in a system with a very low carrier density and, additionally, how the low carrier density might influence the signatures of quantum criticality. A related issue is the nature of the magnetism that is being tuned in such a system. A low carrier density implies a dearth of conduction electrons and, consequently, a small Fermi wave vector. Under these circumstances SDW order is unlikely (but not impossible in principle); however, because the RKKY interaction depends on electrons near as well as deeper inside the Fermi sea (4), RKKY-mediated order is more favorable. Additionally, the cross-over from...

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Section: Discussionmentioning

confidence: 99%

Pressure-tuned quantum criticality in the antiferromagnetic Kondo semimetal CeNi _{2−
δ} As ₂

Luo

Ronning

Wakeham

et al. 2015

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

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“…In figure 2, we present the densities of states as obtained with the below-discussed modified perturbation theory (MPT). Although these DOS are calculated within an approximative method, the qualitatively same picture emerges from the numerically exact Quantum Monte Carlo (QMC) [2,21] and numerical renormalization group calculations (NRG) [18] and can thus be believed to be qualitatively correct.…”

Section: Low-energy Propertiesmentioning

confidence: 96%

“…Second, the self-energy (19) is real, any quasiparticle damping effects as indicated by a finite imaginary part of Σ σ (E) are ignored. The third drawback is the suppression of any feedback mechanism from the conduction band: The latter enters the calculation only via equation (18). This implies that although there are correlation-induced changes in the conduction band (cf.…”

Section: The Hubbard-i Approximationmentioning

confidence: 99%

“…For the case of a periodic array of localized f -levels, the system cannot make available enough conduction electrons to screen all f -moments. This situation is still subject to many investigations [3,21,18,19,23].…”

Section: Low-energy Propertiesmentioning

confidence: 99%

“…The low-energy properties of the PAM have been the subject of intense research [1,16,17,2,18,19]. For the symmetric PAM, defined by n (f ) = n (s) = 1.0 and e f = − U 2 , a Kondo resonance appears centered at µ.…”

Section: Low-energy Propertiesmentioning

confidence: 99%

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Ferromagnetism in the periodic Anderson model. A comparison of spectral density approximation (SDA), modified alloy analogy (MAA) and modified perturbation theory (MPT)

Meyer

Nolting

2000

Eur. Phys. J. B

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Abstract. We compare different approximation schemes for investigating ferromagnetism in the periodic Anderson model. The use of several approximations allows for a detailed analysis of the implications of the respective methods, and also of the mechanisms driving the ferromagnetic transition. For the Kondo limit, our results confirm a previously proposed mechanism leading to ferromagnetic order, namely an RKKY exchange mediated via the formation of Kondo screening clouds in the conduction band. The contrary case is found in the intermediate-valence regime. Here, the bandshift correction ensuring a correct high-energy expansion of the self-energy is essential. Inclusion of damping effects reduces stability of the ferromagnetic phase.

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Quasiparticles in transition metals with strong local correlations: band formation and collective effects

Grewe

2005

Ann. Phys.

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We address the question, whether low lying one-particle excitations in the Fermi-liquid phase of highly correlated electron systems can form well defined bands of nearly stable quasiparticles, and comment on features of a universal band picture for these systems. We outline how to derive a description of instabilities to magnetic, charged ordered or superconducting phases, which bears a close analogy to Stoner theory and lends itself to an interpretation in terms of quasiparticle bands and residual interactions at low temperatures. Concepts and problems are illustrated via calculations for some standard models of solid-state theory using modern many-body techniques like NRG, NCA and DMFT. Differences to conventional band structure theory are pointed out. We shortly comment on the relevance of these questions to the physics of inhomogeneous systems and small particles. The quasiparticle concept and bandsLandau's concept of a Fermi liquid [1] has been of great importance for our understanding of various properties of metals, since it reconciles the picture of independent electrons with our knowledge about their interactions and the correlations thereby induced. In simple metals the conduction bands are broad, the kinetic contribution to the energy is important and electrons acquire a moderate dressing only. They bear an apparent correspondence to the quasiparticles, which constitute the Fermi liquid at low temperatures. This concept also applies to systems of a quite different nature, in particular to the He-3 fluid, in which the fundamental Fermions are atoms with stable electron shells interacting dominantly via a strong shortranged force. Here, the quasiparticles differ considerably from these atoms, incorporating strong backflow effects [2]. It came as a surprise that transition metal compounds can host even more extreme types of Fermi liquids [3], with quasiparticles heavier by a factor of thousand than bare electrons [4]. Although the study of exotic groundstates with superconducting or magnetic order originally lay in the main focus of scientific activity [5,6], it seems worthwhile to consider the "normal" properties of these exotic Fermi liquids, which show strong anomalous temperature dependencies in various quantities like the specific heat or the BIS spectra [7]. Moreover, a number of these systems exhibit a "coherence regime" at low temperatures [7], in which the quasiparticles are supposed to form rather well defined bands. In this connection, the interesting question arises, whether a universal band structure concept for such systems exists, which combines common

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Low-energy scale of the periodic Anderson model

Cited by 135 publications

References 51 publications

Pressure-tuned quantum criticality in the antiferromagnetic Kondo semimetal CeNi _{2−
δ} As ₂

Pressure-tuned quantum criticality in the antiferromagnetic Kondo semimetal CeNi _{2−
δ} As ₂

Ferromagnetism in the periodic Anderson model. A comparison of spectral density approximation (SDA), modified alloy analogy (MAA) and modified perturbation theory (MPT)

Quasiparticles in transition metals with strong local correlations: band formation and collective effects

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Low-energy scale of the periodic Anderson model

Cited by 135 publications

References 51 publications

Pressure-tuned quantum criticality in the antiferromagnetic Kondo semimetal CeNi 2− δ As 2

Pressure-tuned quantum criticality in the antiferromagnetic Kondo semimetal CeNi 2− δ As 2

Ferromagnetism in the periodic Anderson model. A comparison of spectral density approximation (SDA), modified alloy analogy (MAA) and modified perturbation theory (MPT)

Quasiparticles in transition metals with strong local correlations: band formation and collective effects

Contact Info

Product

Resources

About

Pressure-tuned quantum criticality in the antiferromagnetic Kondo semimetal CeNi _{2−
δ} As ₂

Pressure-tuned quantum criticality in the antiferromagnetic Kondo semimetal CeNi _{2−
δ} As ₂