Lifshitz Transition in Kondo Alloys

Burdin, Sébastien; Lacroix, C.

doi:10.1103/physrevlett.110.226403

Cited by 12 publications

(26 citation statements)

References 53 publications

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“…For a given m, unitarity of theη (i) ensures that the annihilators f i,σ,n for all i ∈ B m and all n obey the standard fermion anticommutation relations. With Eqs (37). and(38) the effective Hamiltonian Eq.…”

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confidence: 99%

Strong-coupling limit of depleted Kondo- and Anderson-lattice models

2015

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Fourth-order strong-coupling degenerate perturbation theory is used to derive an effective lowenergy Hamiltonian for the Kondo-lattice model with a depleted system of localized spins. In the strong-J limit, completely local Kondo singlets are formed at the spinful sites which bind a fraction of conduction electrons. The low-energy theory describes the scattering of the excess conduction electrons at the Kondo singlets as well as their effective interactions generated by virtual excitations of the singlets. Besides the Hubbard term, already discussed by Nozières, we find a ferromagnetic Heisenberg interaction, an antiferromagnetic isospin interaction, a correlated hopping and, in more than one dimensions, three-and four-site interactions. The interaction term can be cast into highly symmetric and formally simple spin-only form using the spin of the bonding orbital symmetrically centered around the Kondo singlet. This spin is non-local. We show that, depending on the geometry of the depleted lattice, spatial overlap of the non-local spins around different Kondo singlets may cause ferromagnetic order. This is sustained by a rigorous argument, applicable to the half-filled model, by a variational analysis of the stability of the fully polarized Fermi sea of excess conduction electrons as well as by exact diagonalization of the effective model. A similar fourth-order perturbative analysis is performed for the depleted Anderson lattice in the limit of strong hybridization. Even in a parameter regime where the Schrieffer-Wolff transformation does not apply, this yields the same effective theory albeit with a different coupling constant.

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confidence: 99%

Strong-coupling limit of depleted Kondo- and Anderson-lattice models

2015

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“…Such a probability distribution of Kondo scales, where P (T K = 0) is finite, is also known to yield nFL behavior. 8 In a recent work, a Lifshitz transition 26 is predicted to occur as a function of p, which could lead to nFL behavior in the vicinity of the transition. The interaction of spin fluctuations with disorder close to a quantum critical point is also known to lead to power-law behavior, with a disorder-dependent exponent.…”

Section: Discussionmentioning

confidence: 99%

“…15,[25][26][27] It was shown by Kaul and Vojta 25 that GS appear in a wide range of concentrations leading to nFL behavior. The GS-induced nFL has specific "universal" signatures, albeit dependent on a nonuniversal exponent λ.…”

Section: Discussionmentioning

confidence: 99%

Non-Fermi-liquid behavior from dynamical effects of impurity scattering in correlated Fermi liquids

Vidhyadhiraja

Kumar

2013

Phys. Rev. B

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The interplay of disorder and interactions is a subject of perennial interest. In this work, we have investigated the effect of disorder due to chemical substitution on the dynamics and transport properties of correlated Fermi liquids. A low-frequency analysis in the concentrated and dilute limits shows that the dynamical local potentials arising through disorder averaging generate a linear (in frequency) term in the scattering rate. Such non-Fermi-liquid behavior (nFL) is investigated in detail for Kondo hole substitution in heavy fermions within dynamical mean field theory. We find closed-form expressions for the dependence of the static and linear terms in the scattering rate on substitutional disorder and model parameters. We argue that the low-temperature resistivity will acquire a linear in temperature term, and show that the Drude peak structure in the optical conductivity will disappear beyond a certain disorder p c , that marks the crossover from lattice coherent to single-impurity behavior. A full numerical solution of the dynamical mean field theory equations reveals that the nFL term will show up significantly only in certain regimes, although it is present for any nonzero disorder concentration in principle. We highlight the dramatic changes that occur in the quasiparticle scattering rate in the proximity of p c . Remarkably, we find that the nFL behavior due to dynamical effects of impurity scattering has features that are distinct from those arising through Griffiths singularities or distribution of Kondo scales. Relevance of our findings to experiments on alloyed correlated systems is pointed out.

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“…We analyze here the question of percolation 52,53 for the KAM, that might concern either Kondo or non-Kondo sites 21 . Three-dimensional lattices with further neighbors have a relatively low percolation threshold and coherence can be stabilized down to small values of impurity concentrations.…”

Section: B Percolation Effectsmentioning

confidence: 99%

“…Before analyzing percolation effects within stat-DMFT, we start with with the strong Kondo coupling description given in Ref. 21 and depicted by figure 6. For large J K , the ground state of the system is obtained by forming as many Kondo singlets as possible, and the resulting quasiparticle low energy excitations emerge either from the density n c − x of remaining electrons or from the density x − n c of bachelor Kondo spins.…”

Section: B Percolation Effectsmentioning

confidence: 99%

Breakdown of coherence in Kondo alloys: crucial role of concentration versus band filling

Burdin¹,

Lacroix²

2019

J. Phys.: Condens. Matter

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We study the low energy states of the Kondo alloy model (KAM) as function of the magnetic impurity concentration per site, x, and the conduction electron average site occupation, nc. In previous works, two different Fermi liquid regimes had been identified at strong Kondo coupling JK , that may be separated by a transition at x = nc. Here, we analyze the KAM for finite JK on a Bethe lattice structure. First, using the meanfield coherent potential approximation (DMFT-CPA) which is exact at lattice coordination Z = ∞, we show that the real part of the local potential scattering may be located outside the conduction electron band, revealing a possible breakdown of Luttinger theorem for intermediate values of impurity concentration x. Unusual physical signatures are expected, e.g., in ARPES experiments. In order to take into account fluctuations associated with finite dimensionality, i.e. finite Z, we extend this analyze by also studying the KAM with an adaptation of the statistical-DMFT method that was developped elsewhere. We review the distributions of local potential scattering and their evolution with model parameters: concentration, strength of Kondo coupling, coordination number, local site neighborhood, connection with percolation issue. Relevence for Kondo alloys material with f -electrons is also discussed. arXiv:1810.05383v1 [cond-mat.str-el] 12 Oct 2018 1 n c = 0.25 n c = 0.5 n c = 0.75 J K = D J K = 2D J K = 5D 0 0.2 0.4 0.6 0.8 1 n c = 0.25 n c = 0.5 n c = 0.75 J K = D J K = 2D J K = 5D n c = 0.25 n c = 0.5 n c = 0.75 J K = D J K = 2D J K = 5D n c = 0.25 n c = 0.5 n c = 0.75 J K = D J K = 2D J K = 5D n c = 0.25 n c = 0.5 n c = 0.75 J K = D J K = 2D J K = 5D n c = 0.25 n c = 0.5 n c = 0.75 J K = D J K = 2D J K = 5D n c = 0.25 n c = 0.5 n c = 0.75 J K = D J K = 2D J K = 5D n c = 0.25 n c = 0.5 n c = 0.75 J K = D J K = 2D J K = 5D 0 0.25 0.5 0.75 1 n c = 0.25 n c = 0.5 n c = 0.75 J K = D J K = 2D J K = 5D 0 0.25 0.5 0.75 1 n c = 0.25 n c = 0.5 n c = 0.75 J K = D J K = 2D J K = 5D 0 0.25 0.5 0.75 1 n c = 0.25 n c = 0.5 n c = 0.75 J K = D J K = 2D J K = 5D 0 0.25 0.5 0.75 1 n c = 0.25 n c = 0.5 n c = 0.75 J K = D J K = 2D J K = 5D 0 0.25 0.5 0.75 1 n c = 0.25 n c = 0.5 n c = 0.75 J K = D J K = 2D J K = 5D 0 0.25 0.5 0.75 1 n c = 0.25 n c = 0.5 n c = 0.75 J K = D J K = 2D J K = 5D 0 0.25 0.5 0.75 1

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Lifshitz Transition in Kondo Alloys

Cited by 12 publications

References 53 publications

Strong-coupling limit of depleted Kondo- and Anderson-lattice models

Strong-coupling limit of depleted Kondo- and Anderson-lattice models

Non-Fermi-liquid behavior from dynamical effects of impurity scattering in correlated Fermi liquids

Breakdown of coherence in Kondo alloys: crucial role of concentration versus band filling

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