Ground-state phase diagram of the one-dimensional extended Hubbard model

Cannon, Joel W.; Scalettar, Richard; Fradkin, Eduardo

doi:10.1103/physrevb.44.5995

Cited by 72 publications

(49 citation statements)

References 14 publications

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“…The phase diagram then has a shape very similar to that of the half-filled 1D extended Hubbard model ͑EHM͒. 29,[32][33][34] In the half-filled EHM, as the nearest-neighbor Coulomb repulsion V is increased for fixed U, there is a transition from AFM to CDW order. This transition is continuous for small U and first order for U Ͼ U m .…”

Section: First-order Transitionmentioning

confidence: 90%

Phase diagram of the one-dimensional Hubbard-Holstein model at half and quarter filling

2007

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The Hubbard-Holstein model is one of the simplest to incorporate both electron-electron and electronphonon interactions. In one dimension at half filling, the Holstein electron-phonon coupling promotes on-site pairs of electrons and a Peierls charge-density wave, while the Hubbard on-site Coulomb repulsion U promotes antiferromagnetic correlations and a Mott insulating state. Recent numerical studies have found a possible third intermediate phase between Peierls and Mott states. From direct calculations of charge and spin susceptibilities, we show that ͑i͒ as the electron-phonon coupling is increased, first a spin gap opens, followed by the Peierls transition. Between these two transitions, the metallic intermediate phase has a spin gap, no charge gap, and properties similar to the negative-U Hubbard model.

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Section: First-order Transitionmentioning

confidence: 90%

Phase diagram of the one-dimensional Hubbard-Holstein model at half and quarter filling

2007

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“…The comparison also shows that the TS phase in 1D extends beyond the expectations of the HF BCS results. This is particularly clear for t AB ∼ t AA = t BB and U ∼ 2V , and is probably related to the fact that, in the continuum limit theory, the backscattering and Umklapp terms coming from the U and V terms of the Hamiltonian (ultimately responsible of the insulating behaviour), nearly cancel each other on the line U = 2V 54,56 .…”

Section: Phase Diagram Obtained From Topological Transitionsmentioning

confidence: 99%

“…However, these quantities as well as different correlation functions vary smoothly at the transition and it is very difficult to obtain accurate boundaries [52][53][54][55] . Instead, the use of topological numbers as order parameters necessarily leads to sharp transitions.…”

Section: Phase Diagram Obtained From Topological Transitionsmentioning

confidence: 99%

“…The best previous numerical methods to determine phase diagrams of this type were based on the size dependence of SDW and CDW order parameters, and their probability densities in a Monte Carlo sampling 38,52,54 . However, these quantities as well as different correlation functions vary smoothly at the transition and it is very difficult to obtain accurate boundaries [52][53][54][55] .…”

Section: Phase Diagram Obtained From Topological Transitionsmentioning

confidence: 99%

“…There exists a metallic phase (the detailed nature of which will be discussed later) for small values of U and V , which shrinks as t AB → t. When t AB = t (Hubbard limit), several results indicate that there is no M phase, except, eventually, on the second-order transition line between the CDW and SDW phases, that ends at a tricritical point. The position of this point is, to date, not well determined and should be around U ∼ 2V ∼ 4t [52][53][54][55][56] .…”

Section: Introductionmentioning

confidence: 99%

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Superconductivity with s and p symmetries in an extended Hubbard model with correlated hopping

et al. 1998

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We consider a generalized Hubbard model with on-site and nearest-neighbour repulsions U and V respectively, and nearest-neighbour hopping for spin up (down) which depends on the total occupation n b of spin down (up) electrons on both sites involved. The hopping parameters are tAA, tAB and tBB for n b = 0, 1, 2 respectively. We briefly summarize results which support that the model exhibits s-wave superconductivity for certain parameters and extend them by studying the Berry phases. Using a generalized Hartree-Fock(HF) BCS decoupling of the two and three-body terms, we obtain that at half filling, for tAB < tAA = tBB and sufficiently small U and V the model leads to triplet p-wave superconductivity for a simple cubic lattice in any dimension. In one dimension, the resulting phase diagram is compared with that obtained numerically using two quantized Berry phases (topological numbers) as order parameters. While this novel method supports the previous results, there are quantitative differences.

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