Excitation Spectrum of One-dimensional Extended Ionic Hubbard Model

Abstract

We use Perturbative Continuous Unitary Transformations (PCUT) to study the one dimensional Extended Ionic Hubbard Model (EIHM) at half-filling in the band insulator region. The extended ionic Hubbard model, in addition to the usual ionic Hubbard model, includes an inter-site nearest-neighbor (n.n.) repulsion, $V$. We consider the ionic potential as unperturbed part of the Hamiltonian, while the hopping and interaction (quartic) terms are treated as perturbation. We calculate total energy and ionicity in the ground state. Above the ground state, (i) we calculate the single particle excitation spectrum by adding an electron or a hole to the system. (ii) the coherence-length and spectrum of electron-hole excitation are obtained. Our calculations reveal that for V=0, there are two triplet bound state modes and three singlet modes, two anti-bound states and one bound state, while for finite values of $V$ there are four excitonic bound states corresponding to two singlet and two triplet modes. The major role of on-site Coulomb repulsion $U$ is to split singlet and triplet collective excitation branches, while $V$ tends to pull the singlet branches below the continuum to make them bound states.

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References in corpus (29)

• Perturbation Theory by Flow Equations: Dimerized and Frustrated S=1/2 Chain
• Low-energy effective theory of the toric code model in a parallel field
• From band insulator to Mott insulator in one dimension
• The Structure of Operators in Effective Particle-Conserving Models
• Can correlations drive a band insulator metallic?
• Quantum critical behavior of the one-dimensional ionic Hubbard model
• Quantum Monte Carlo Study of an Interaction-Driven Band Insulator to Metal Transition
• Flow equations for band--matrices
• Spectral Properties of Magnetic Excitations in Cuprate Two-Leg Ladder Systems
• Metallic phase in the two-dimensional ionic Hubbard model
• Linked Cluster Series Expansions for Two-Particle Bound States
• Exact Bond Ordered Ground State for the Transition Between the Band and the Mott Insulator
• Predicting a Gapless Spin-1 Neutral Collective Mode branch for Graphite
• Bound states in two-dimensional spin systems near the Ising limit: A quantum finite-lattice study
• High Order Perturbation Theory for Spectral Densities of Multi-Particle Excitations: S=1/2 Two-Leg Heisenberg Ladder
• Dynamic Structure Factor of the Two-Dimensional Shastry-Sutherland Model
• Adapted continuous unitary transformation to treat systems with quasiparticles of finite lifetime
• Insulating behavior with spin and charge order in the ionic Hubbard model
• Spectral properties of the dimerized and frustrated $S=1/2$ chain
• Raman Response of Magnetic Excitations in Cuprate Ladders and Planes
• On the valence-bond solid phase of the crossed-chain quantum spin model
• Renormalization by Continuous Unitary Transformations: One-Dimensional Spinless Fermions
• Nonlinear lattice relaxation of photoexcited diplatinum-halide chain compounds
• Series expansion analysis of a tetrahedral cluster spin chain
• Flow Equations for the Ionic Hubbard Model
• Neutral triplet Collective Mode as a new decay channel in Graphite
• Classical Analogue of the Ionic Hubbard Model
• Correlation effects for semiconducting single wall carbon nanotube: a density matrix renormalization group study
• Two-Dimensionality of Magnetic Excitations on the Trellis Lattice: (La,Sr,Ca)${}_{14}$Cu${}_{24}$O${}_{41}$ and SrCu${}_2$O${}_3$

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• Massive spinons in $S=1/2$ spin chains: spinon-pair operator representation
• Dynamic structure factor of the antiferromagnetic Kitaev model in large magnetic fields
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• Dynamical Charge Structure Factor of a One-Dimensional Ionic Hubbard Model in the Low-Energy Region