Single-hole dynamics in the half-filled two-dimensional Kondo-Hubbard model

Feldbacher, M.; Jurecka, Christoph; Assaad, Fakher F.; Brenig, Wilhelm

doi:10.1103/physrevb.66.045103

Cited by 17 publications

(15 citation statements)

References 21 publications

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“…For the KNM and up to the lowest couplings we have considered the effective mass at p p p = (π, π) increases as a function of decreasing coupling strength but does not seem to diverge at finite values of J ⊥ /J . Precisely the same conclusion is reached in the framework of the KLM [4] and UKLM [5].…”

Section: B Hole Dynamicssupporting

confidence: 67%

Single-hole dynamics in the Kondo necklace and bilayer Heisenberg models on a square lattice

Brünger

Assaad

2006

Phys. Rev. B

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We study single hole dynamics in the bilayer Heisenberg and Kondo Necklace models. Those models exhibit a magnetic order-disorder quantum phase transition as a function of the interlayer coupling J ⊥ . At strong coupling in the disordered phase, both models have a single-hole dispersion relation with band maximum at p p p = (π, π) and an effective mass at this p p p−point which scales as the hopping matrix element t. In the Kondo Necklace model, we show that the effective mass at p p p = (π, π) remains finite for all considered values of J ⊥ such that the strong coupling features of the dispersion relation are apparent down to weak coupling. In contrast, in the bilayer Heisenberg model, the effective mass diverges at a finite value of J ⊥ . This divergence of the effective mass is unrelated to the magnetic quantum phase transition and at weak coupling the dispersion relation maps onto that of a single hole doped in a planar antiferromagnet with band maximum at p p p = (π/2, π/2). We equally study the behavior of the quasiparticle residue in the vicinity of the magnetic quantum phase transition both for a mobile and static hole. In contrast to analytical approaches, our numerical results do not unambiguously support the fact that the quasiparticle residue of the static hole vanishes in the vicinity of the critical point. The above results are obtained with a generalized version of the loop algorithm to include single hole dynamics on lattice sizes up to 20 × 20.

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Section: B Hole Dynamicssupporting

confidence: 67%

Single-hole dynamics in the Kondo necklace and bilayer Heisenberg models on a square lattice

Brünger

Assaad

2006

Phys. Rev. B

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“…The qualitative difference between the pure Hubbard and Kondo-Hubbard model, even at arbitrarily weak Kondo coupling, is reminiscent of similar results for the Fermi Kondo-Hubbard model obtained in Ref. [15]. That the inclusion of small inter-band interactions (which are often relevant in real materials) can have such a dramatic effect on the Bose Hubbard phase diagram underscores the importance of generalizing optical lattice simulations to include orbital degrees of freedom.…”

Section: Introductionmentioning

confidence: 60%

Phase diagram of the bosonic Kondo-Hubbard model

Foss‐Feig

Rey

2011

Phys. Rev. A

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We study a bosonic version of the Kondo lattice model with an on-site repulsion in the conduction band, implemented with alkali atoms in two bands of an optical lattice. Using both weak and strongcoupling perturbation theory, we find that at unit filling of the conduction bosons the superfluid to Mott insulator transition should be accompanied by a magnetic transition from a ferromagnet (in the superfluid) to a paramagnet (in the Mott insulator). Furthermore, an analytic treatment of Gutzwiller mean-field theory reveals that quantum spin fluctuations induced by the Kondo exchange cause the otherwise continuous superfluid to Mott-insulator phase transition to be first order. We show that lattice separability imposes a serious constraint on proposals to exploit excited bands for quantum simulations, and discuss a way to overcome this constraint in the context of our model by using an experimentally realized non-separable lattice. A method to probe the first-order nature of the transition based on collapses and revivals of the matter-wave field is also discussed.

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“…Ref. 57 discussed the photoemission spectrum of a conduction electron in an insulator in the vicinity of the magnetic transition 55 . Let us focus on the minimum energy of its dispersion.…”

Section: E Applicationsmentioning

confidence: 99%

Impurity quantum phase transitions

Vojta

2006

Philosophical Magazine

172

227

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We review recent work on continuous quantum phase transitions in impurity models, both with fermionic and bosonic baths -these transitions are interesting realizations of boundary critical phenomena at zero temperature. The models with fermion bath are generalizations of the standard Kondo model, with the common feature that Kondo screening of the localized spin can be suppressed due to competing processes. The models with boson bath are related to the spin-boson model of dissipative two-level systems, where the interplay between tunneling and friction results in multiple phases. The competition inherent to all models can generate unstable fixed points associated with quantum phase transitions, where the impurity properties undergo qualitative changes. Interestingly, certain impurity transitions feature both lower-critical and upper-critical "dimensions" and allow for epsilon-type expansions. We present results for a number of observables, obtained by both analytical and numerical renormalization group techniques, and make connections to experiments.

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Single-hole dynamics in the half-filled two-dimensional Kondo-Hubbard model

Cited by 17 publications

References 21 publications

Single-hole dynamics in the Kondo necklace and bilayer Heisenberg models on a square lattice

Single-hole dynamics in the Kondo necklace and bilayer Heisenberg models on a square lattice

Phase diagram of the bosonic Kondo-Hubbard model

Impurity quantum phase transitions

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