Interaction of a magnetic impurity with strongly correlated conduction electrons

Schork, Tom; Fulde, Peter

doi:10.1103/physrevb.50.1345

Cited by 39 publications

(42 citation statements)

References 18 publications

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“…However, more careful considerations suggest [16][17][18][19] that electron-electron interactions can cause new spin-exchange channels to open up between a local moment and the conduction sea. There are several mechanisms by which these new spin exchange channels can open up, including the vicinity to a quantum critical point, 17 interactions in the conduction sea, 18,19 and intra-atomic Hunds interactions.…”

Section: Multichannel Scattering Effects In Interacting Kondo Latmentioning

confidence: 99%

Co-operative Kondo effect in the two-channel Kondo lattice

Coleman¹,

Tsvelik²,

Andrei³

1999

Phys. Rev. B

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We examine how the properties of a single-channel Kondo lattice model are modified by additional screening channels. Contrary to current wisdom, additional screening channels appear to constitute a relevant perturbation which destabilizes the Fermi liquid. This instability involves two stages. When a heavy Fermi surface develops, it generates zero modes for Kondo singlets to fluctuate between screening channels of different symmetry, producing a divergent composite pair susceptibility. Additional screening channels couple to these divergent fluctuations, promoting an instability into a superconducting state with long-range composite order. We discuss possible implications for heavy fermion superconductivity. ͓S0163-1829͑99͒04629-9͔

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Section: Multichannel Scattering Effects In Interacting Kondo Latmentioning

confidence: 99%

Co-operative Kondo effect in the two-channel Kondo lattice

Coleman¹,

Tsvelik²,

Andrei³

1999

Phys. Rev. B

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“…The generator of the canonical transformation (S) follows from the requirement that [H 0 ϩ H lead , S] ϭ H hyb , and can be formally expressed as (40), with the coupling constant g ϳ ut 2 ͞⌬ 2 , which gives rise to the expression for g stated earlier once we recognize that, in itinerant ferromagnets, 0 u ϳ 1. The conduction electron dispersion in each lead is Zeeman split: ˜k i ϭ k ϩ m i .…”

Section: Formal Detailsmentioning

confidence: 99%

Quantum criticality in ferromagnetic single-electron transistors

Kirchner

Zhu

et al. 2005

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

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Considerable evidence exists for the failure of the traditional theory of quantum critical points, pointing to the need to incorporate novel excitations. The destruction of Kondo entanglement and the concomitant critical Kondo effect may underlie these emergent excitations in heavy fermion metals (a prototype system for quantum criticality), but the effect remains poorly understood. Here, we show how ferromagnetic single-electron transistors can be used to study this effect. We theoretically demonstrate a gate-voltage-induced quantum phase transition. The critical Kondo effect is manifested in a fractional-power-law dependence of the conductance on temperature (T). The AC conductance and thermal noise spectrum have related power-law dependences on frequency ( ) and, in addition, show an ͞T scaling. Our results imply that the ferromagnetic nanostructure constitutes a realistic model system to elucidate magnetic quantum criticality that is central to the heavy fermions and other bulk materials with non-Fermi liquid behavior.Kondo effect ͉ non-Fermi liquid ͉ quantum phase transition A quantum critical point (QCP) occurs at zero temperature as a system changes from one ground state to another, and it controls physical properties over a wide region in the phase diagram at finite temperatures (1-6). Electrons in condensed matter are traditionally described as a Fermi liquid, a collection of essentially independent particles. Near a QCP, however, electrons are coupled to each other in a singular fashion; how such electron correlations lead to non-Fermi liquid states is an open issue that is central to a variety of strongly correlated systems, including high-temperature superconductors and heavy fermion metals (5). Single-electron devices play a unique role in the study of correlated electronic states, in addition to their potential application to quantum electronics and quantum information processing. The Fermi liquid state has been studied systematically in semiconductor quantum dots and singlemolecule transistors (7)(8)(9)(10)(11)(12)(13)(14). Here, the low-energy excitations of the normal metal leads are electrons near their respective Fermi energies. These itinerant electrons are entangled with the magnetic moment localized on the dot, producing a Kondo resonance. The manifestation of the Kondo resonance in the conductance spectrum was predicted (7, 8) and was subsequently observed in semiconductor quantum dots (9-11) and in singlemolecule transistors (12)(13)(14). Ingenious proposals and structures (15-17) have been put forth to model the non-Fermi liquid states associated with the multichannel Kondo systems and the twoimpurity Kondo effect (5). The experimental observation of the non-Fermi liquid states is, however, still lacking, in part because such states of quantum-impurity models are not robust, requiring special symmetries that are difficult to realize (5).Recently, it has become possible to fabricate single-electron transistors with leads made of ferromagnetic metals (18). Fig. 1a provides a schematic illu...

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“…Electron-electron interactions, such as Hund's interactions, can induce the opening of new spin-exchange channels between the local moments and the conduction electrons. [18][19][20] For an impurity magnetic ion, the Kondo effect develops exclusively in the strongest screening channel due to the local symmetry which preserves the channel quantum number of scattered electrons. In a lattice, however, a conduction electron can change symmetry channels as it moves from one spin site to another.…”

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confidence: 99%

Two-channel Kondo lattice model on a ladder studied by the density-matrix renormalization-group method

et al. 2001

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Using the density matrix renormalization group (DMRG) method we study a two-channel Kondo lattice model on a half filled ladder. Our model involves an on-site s-wave and a nearest neighbor dwave coupling between the local moments and the conduction electrons on the ladder. By changing the relative strength of the two Kondo interactions we examine the evolution of the system from a conventional Kondo insulator with a singlet at each site to a new kind of semimetallic state formed by overlapping of Zhang-Rice-like singlets. The DMRG is used to study how the spin and charge correlation functions evolve between these two regimes.

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Interaction of a magnetic impurity with strongly correlated conduction electrons

Cited by 39 publications

References 18 publications

Co-operative Kondo effect in the two-channel Kondo lattice

Co-operative Kondo effect in the two-channel Kondo lattice

Quantum criticality in ferromagnetic single-electron transistors

Two-channel Kondo lattice model on a ladder studied by the density-matrix renormalization-group method

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