Excitation spectrum of one-dimensional extended ionic Hubbard model

Hafez, Mohsen; Jafari, S. A.

doi:10.1140/epjb/e2010-10509-x

Cited by 16 publications

(23 citation statements)

References 53 publications

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“…Once the parameters t and U are specified, the mean field equations (40) have to be solved self-consistently for the expectation values (38). The results are show in Fig.…”

Section: Beyond the Transition Point: A Mean Field Studymentioning

confidence: 99%

Dispersive excitations in one-dimensional ionic Hubbard model

2014

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A detailed study of the one-dimensional ionic Hubbard model with interaction U is presented. We focus on the band insulating (BI) phase and the spontaneously dimerized insulating (SDI) phase which appears on increasing U . By a recently introduced continuous unitary transformation [Krull et al. Phys. Rev. B 86, 125113 (2012)] we are able to describe the system even close to the phase transition from BI to SDI although the bare perturbative series diverges before the transition is reached. First, the dispersion of single fermionic quasiparticles is determined in the full Brillouin zone. Second, we describe the binding phenomena between two fermionic quasiparticles leading to an S = 0 and to an S = 1 exciton. The latter corresponds to the lowest spin excitation and defines the spin gap which remains finite through the transition from BI to SDI. The former becomes soft at the transition indicating that the SDI corresponds to a condensate of these S = 0 excitons. This view is confirmed by a BCS mean field theory for the SDI phase.

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“…Once the parameters t and U are specified, the mean field equations (40) have to be solved self-consistently for the expectation values (38). The results are show in Fig.…”

Section: Beyond the Transition Point: A Mean Field Studymentioning

confidence: 99%

Dispersive excitations in one-dimensional ionic Hubbard model

2014

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“…The nature of transition between BI and MI and question of possible phases between BI and MI has been the subject of debates. This model in arbitrary dimension and at half‐filling has been suited by many authors employing various techniques …”

Section: Introductionmentioning

confidence: 99%

Quantum Integrability of 1D Ionic Hubbard Model

Hosseinzadeh

Jafari

2020

Annalen der Physik

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The quantum integrability of the 1D ionic Hubbard model (IHM) is established using two independent numerical methods, namely i) energy level spacing statistics and ii) occupation profile of one‐particle density matrix (OPDM) eigen‐values. Both methods suggest that the 1D IHM is integrable. The calculations of energy level statistics reproduce the known results for the standard Hubbard model. Upon turning on the the ionic term, the energy level spacing distribution of this model continues to obey the Poissonian distribution. Occupation patterns as extracted from OPDM indicate that quasi‐particles are sharpened upon increasing the ionic potential. This is evidenced by a larger jump in the occupation number distribution.

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“…This includes the full dependence on the momentum in contrast to many purely numerical approaches. In previous work, this had been achieved in the BI phase only 18,31,32 starting from fermionic quasiparticles.…”

Section: Discussionmentioning

confidence: 99%

From gapped excitons to gapless triplons in one dimension

2015

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Often, exotic phases appear in the phase diagrams between conventional phases. Their elementary excitations are of particular interest. Here, we consider the example of the ionic Hubbard model in one dimension. This model is a band insulator (BI) for weak interaction and a Mott insulator (MI) for strong interaction. Inbetween, a spontaneously dimerized insulator (SDI) occurs which is governed by energetically low-lying charge and spin degrees of freedom. Applying a systematically controlled version of the continuous unitary transformations (CUTs) we are able to determine the dispersions of the elementary charge and spin excitations and of their most relevant bound states on equal footing. The key idea is to start from an externally dimerized system using the relative weak interdimer coupling as small expansion parameter which finally is set to unity to recover the original model.

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Excitation spectrum of one-dimensional extended ionic Hubbard model

Cited by 16 publications

References 53 publications

Dispersive excitations in one-dimensional ionic Hubbard model

Dispersive excitations in one-dimensional ionic Hubbard model

Quantum Integrability of 1D Ionic Hubbard Model

From gapped excitons to gapless triplons in one dimension

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