First- and second-order phase transitions in the Holstein-Hubbard model

Koller, Winfried; Meyer, D.; Ōno, Yoshiaki; Hewson, A. C.

doi:10.1209/epl/i2003-10228-6

Cited by 90 publications

(117 citation statements)

References 22 publications

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“…2); the electron motion, even if slowed down by e-ph coupling, can take advantage of the smaller energy cost associated to double occupation, and this results in a decrease of m * with respect to the λ = 0 value. As the phonon-induced attraction overcomes the Hubbard repulsion, the two effect of phonons (localizing tendency to self-trap and to form local pairs) are cooperative, leading to a sharp firstorder transition to the BPI for strong enough U and small γ 12 .…”

Section: Quasiparticle Weight Phonon Displacement and Bipolaron mentioning

confidence: 99%

Gutzwiller scheme for electrons and phonons: The half-filled Hubbard-Holstein model

et al. 2008

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We analyze the ground-state properties of strongly-correlated electrons coupled with phonons by means of a generalized Gutzwiller wavefunction which includes phononic degrees of freedom. We study in detail the paramagnetic half-filled Hubbard-Holstein model, where the electron-electron interaction can lead to a Mott transition, and the electron-phonon coupling to a bipolaronic transition. We critically discuss the quality of the proposed wavefunction in describing the various transitions and crossovers that occur as a function of the parameters. Previous variational attempts are recovered as particular choices of the wavefunction, while keeping all the variational freedom allows to access regions of the phase diagram otherwise inaccessible within previous variational approaches.

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Section: Quasiparticle Weight Phonon Displacement and Bipolaron mentioning

confidence: 99%

Gutzwiller scheme for electrons and phonons: The half-filled Hubbard-Holstein model

et al. 2008

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“…(1), we use the DMFT in which the model is mapped onto an effective single impurity two-orbital Anderson model coupled with Jahn-Teller phonons. 13,20) The local Green's function G f lσ (iω n ) and the local selfenergy Σ lσ (iω n ) for the f -electron satisfy the following selfconsistency conditions:…”

Section: J P H Y S S O C J P N D O W N L O a D E D F R O M J mentioning

confidence: 99%

Heavy Fermions due to Cooperative Effects of Coulomb and Electron–Phonon Interactions in the Two-Orbital Periodic Anderson Model

Mitsumoto

Ōno

2011

J. Phys. Soc. Jpn.

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Using the dynamical mean-field theory, we investigate the two-orbital periodic Anderson model including both the Coulomb interaction U between f-electrons and the electron-phonon interaction g which couple the local orbital fluctuations of f -electrons with Jahn-Teller phonons. It is found that the heavy fermion state caused by U is largely enhanced due to the effect of g. In the heavy fermion state for large U and g, both the orbital and lattice fluctuations are enhanced, while the charge (valence) and spin fluctuations are suppressed; this is a nonmagnetic origin of the heavy fermions. The effect of the mass enhancement for the case with twofold-degenerate phonon mode is larger than that for one phonon mode. The obtained results show a possible nonmagnetic origin of the heavy fermion state recently observed in SmOs 4 Sb 12 .

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“…8 Recently, the HH model was studied with DMFT in combination with the numerical renormalization group (NRG) at half-filling at zero temperature. 4,9 The NRG method has also been successfully applied to AH model 6,7 , and almost exact results on the electron and phonon spectral functions have been obtained. However, it is still desirable to develop an analytic scheme in spite of its approximate nature since it helps us to understand the underlying physics in more clear and intuitive way.…”

Section: Introductionmentioning

confidence: 99%

Slave-boson approach to the infinite-UAnderson-Holstein impurity model

Lee

Choi²

2004

Phys. Rev. B

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The infinite-U Anderson-Holstein impurity model is studied with a focus on the interplay between the strong electron correlation and the weak electron-phonon interaction. The slave boson method has been employed in combination with the large degeneracy expansion (1/N ) technique. The charge and spin susceptibilities and the phonon propagator are obtained in the approximation scheme where the saddle point configuration and the Gaussian 1/N fluctuations are taken into account. The spin susceptibility is found not to be renormalized by electron-phonon interaction, while the charge susceptibility is renormalized. From the renormalized charge susceptibility the Kondo temperature is found to increase by the electron-phonon interaction. It turns out that the bosonic 1/N Gaussian fluctuations play a very crucial role, in particular, for the phonon propagator.

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First- and second-order phase transitions in the Holstein-Hubbard model

Cited by 90 publications

References 22 publications

Gutzwiller scheme for electrons and phonons: The half-filled Hubbard-Holstein model

Gutzwiller scheme for electrons and phonons: The half-filled Hubbard-Holstein model

Heavy Fermions due to Cooperative Effects of Coulomb and Electron–Phonon Interactions in the Two-Orbital Periodic Anderson Model

Slave-boson approach to the infinite-UAnderson-Holstein impurity model

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