Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical review. B, Condensed matter

Quantum and thermal charge-transfer fluctuations for neutral-ionic phase transitions in the one-dimensional extended Hubbard model with alternating potentials

Kenji Yonemitsu

Published Feb 7, 2002• 8 citations
Publisher

Abstract

Effects of quantum and thermal fluctuations on transitions between the ionic phase and the neutral phase are studied by applying the finite-temperature density-matrix renormalization-group method to the one-dimensional extended Hubbard model with alternating potentials at half filling. Charge-transfer fluctuations lower the energy of the neutral phase more than that of the ionic phase, which is in contrast to the spin fluctuations favoring the ionic phase. As a consequence, with increasing intermolecular overlap between the neighboring donor and acceptor sites, we expect a spin-fluctuation-induced transition from the neutral phase to the ionic phase, and a charge-transfer-fluctuation-induced transition from the ionic phase to the neutral phase, near the phase boundary. Relevance to a recently observed phase transition in a new class of mixed-stack charge-transfer complexes is discussed.

DOI
10.1103/physrevb.65.085105

Related papers

Electronic and Lattice Dynamics in the Photoinduced Ionic-to-Neutral Phase Transition in a One-Dimensional Extended Peierls–Hubbard Model

Naoyuki Miyashita, Makoto Kuwabara, Kenji Yonemitsu

Real-time dynamics of charge density and lattice displacements is studied during photoinduced ionic-to-neutral phase transitions by using a one-dimensional extended Peierls-Hubbard model with alternating potentials for the one-dimensional mixed-stack charge-transfer complex, TTF-CA. The time-dependent Schrödinger equation and the classical equation of motion are solved for the electronic and lattice parts, respectively. We show how neutral domains grow in the ionic background. As the photoexcitation becomes intense, more neutral domains are created. Above threshold intensity, the neutral phase is finally achieved. After the photoexcitation, ionic domains with wrong polarization also appear. They quickly reduce the averaged staggered lattice displacement, compared with the averaged ionicity. As the degree of initial lattice disorder increases, more solitons appear between these ionic domains with different polarizations, which obstruct the growth of neutral domains and slow down the transition.

arXiv:cond-mat/0211487•Journal of the Physical Society of Japan•Sep 15, 2003•29 citations

Nature of the insulating phases in the half-filled ionic Hubbard model

A. P. Kampf, Michael Sekania, G. I. Japaridze +1 more

We investigate the ground-state phase diagram of the one-dimensional 'ionic' Hubbard model with an alternating periodic potential at half-filling by numerical diagonalization of finite systems with the Lanczos and density matrix renormalization group methods. We identify an insulator–insulator phase transition from a band to a correlated insulator with simultaneous charge and bond-charge order. The transition point is characterized by the vanishing of the optical excitation gap while simultaneously the charge and spin gaps remain finite and equal. Indications for a possible second transition into a Mott-insulator phase are discussed.

arXiv:cond-mat/0304697•Journal of Physics Condensed Matter•Aug 15, 2003•76 citations

Quantum critical behavior of the one-dimensional ionic Hubbard model

Salvatore R. Manmana, V. Meden, R. M. Noack +1 more

We study the zero-temperature phase diagram of the half-filled one-dimensional ionic Hubbard model. This model is governed by the interplay of the on-site Coulomb repulsion and an alternating one-particle potential. Various many-body energy gaps, the charge-density-wave and bond-order parameters, the electric as well as the bond-order susceptibilities, and the density-density correlation function are calculated using the density-matrix renormalization group method. In order to obtain a comprehensive picture, we investigate systems with open as well as periodic boundary conditions and study the physical properties in different sectors of the phase diagram. A careful finite-size scaling analysis leads to results which give evidence in favor of a scenario with two quantum critical points and an intermediate spontaneously dimerized phase. Our results indicate that the phase transitions are continuous. Using a scaling ansatz we are able to read off critical exponents at the first critical point. In contrast to a bosonization approach, we do not find Ising critical exponents. We show that the low-energy physics of the strong-coupling phase can only partly be understood in terms of the strong-coupling behavior of the ordinary Hubbard model.

arXiv:cond-mat/0307741•Physical Review B•Oct 29, 2004•117 citations

Study of the ionic Peierls-Hubbard model using density matrix renormalization group methods

Yu‐Zhong Zhang, Chao Wu, Hua Lin

Density matrix renormalization group methods are used to investigate the quantum phase diagram of a one-dimensional half-filled ionic Peierls-Hubbard model at the antiadiabatic limit where quantum phonon fluctuations are taken into account partially. We found that two continuous phase transitions always exist from dimerized spin-gapped (bond-order-wave) state to band-insulator and undimerized spin-gapless (Mott-insulator) phase while undimerized spin-gapless phase vanishes at the adiabatic limit. Our results indicate that quantum phonon fluctuations, electron-electron interaction, and ionic potential combine in the formation of the bond-order wave phase.

arXiv:cond-mat/0401535•Physical Review B•Sep 28, 2005•6 citations

Ground-state phase diagram of the one-dimensional Hubbard model with an alternating chemical potential

Hiromi Otsuka, Masaaki Nakamura

We investigate the ground-state phase diagram of the one-dimensional half-filled Hubbard model with an alternating potential---a model for the charge-transfer organic materials and the ferroelectric perovskites. We numerically determine the global phase diagram of this model using the level-crossing and the phenomenological renormalization-group methods based on the exact diagonalization calculations. Our results support the mechanism of the double phase transitions between Mott and band insulators pointed out by Fabrizio, Gogolin, and Nersesyan [Phys. Rev. Lett. 83, 2014 (1999)]: We confirm the existence of the spontaneously dimerized phase as an intermediate state. Further we provide numerical evidence to check the criticalities on the phase boundaries. Especially, we perform the finite-size-scaling analysis of the excitation gap to show the two-dimensional Ising transition in the charge part. On the other hand, we confirm that the dimerized phase survives in the strong-coupling limit, which is one of the resultants of competition between the ionicity and correlation effects.

arXiv:cond-mat/0403630•Physical Review B•Apr 8, 2005•34 citations

Unified phase diagram of models exhibiting a neutral-ionic transition

Örs Legeza, K. Buchta, Jenő Sólyom

We have studied the neutral-ionic transition in organic mixed-stack compounds. A unified model has been derived which, in limiting cases, is equivalent to the models proposed earlier, the donor-acceptor model, and the ionic Hubbard model. Detailed numerical calculations have been performed on this unified model with the help of the density-matrix renormalization-group (DMRG) procedure calculating excitation gaps, ionicity, lattice site entropy, two-site entropy, and the dimer order parameter on long chains and the unified phase diagram has been determined.

arXiv:cond-mat/0511082•Physical Review B•Apr 21, 2006•23 citations
Effects of quantum and thermal fluctuations on transitions between the ionic phase and the neutral phase are studied by applying the finite-temperature density-matrix renormalization-group method to the one-dimensional extended Hubbard model with alternating potentials at half filling. Charge-transfer fluctuations lower the energy of the neutral phase more than that of the ionic phase, which is in contrast to the spin fluctuations favoring the ionic phase. As a consequence, with increasing intermolecular overlap between the neighboring donor and acceptor sites, we expect a spin-fluctuation-induced transition from the neutral phase to the ionic phase, and a charge-transfer-fluctuation-induced transition from the ionic phase to the neutral phase, near the phase boundary. Relevance to a recently observed phase transition in a new class of mixed-stack charge-transfer complexes is discussed.
Real-time dynamics of charge density and lattice displacements is studied during photoinduced ionic-to-neutral phase transitions by using a one-dimensional extended Peierls-Hubbard model with alternating potentials for the one-dimensional mixed-stack charge-transfer complex, TTF-CA. The time-dependent Schrödinger equation and the classical equation of motion are solved for the electronic and lattice parts, respectively. We show how neutral domains grow in the ionic background. As the photoexcitation becomes intense, more neutral domains are created. Above threshold intensity, the neutral phase is finally achieved. After the photoexcitation, ionic domains with wrong polarization also appear. They quickly reduce the averaged staggered lattice displacement, compared with the averaged ionicity. As the degree of initial lattice disorder increases, more solitons appear between these ionic domains with different polarizations, which obstruct the growth of neutral domains and slow down the transition.
We investigate the ground-state phase diagram of the one-dimensional 'ionic' Hubbard model with an alternating periodic potential at half-filling by numerical diagonalization of finite systems with the Lanczos and density matrix renormalization group methods. We identify an insulator–insulator phase transition from a band to a correlated insulator with simultaneous charge and bond-charge order. The transition point is characterized by the vanishing of the optical excitation gap while simultaneously the charge and spin gaps remain finite and equal. Indications for a possible second transition into a Mott-insulator phase are discussed.
We study the zero-temperature phase diagram of the half-filled one-dimensional ionic Hubbard model. This model is governed by the interplay of the on-site Coulomb repulsion and an alternating one-particle potential. Various many-body energy gaps, the charge-density-wave and bond-order parameters, the electric as well as the bond-order susceptibilities, and the density-density correlation function are calculated using the density-matrix renormalization group method. In order to obtain a comprehensive picture, we investigate systems with open as well as periodic boundary conditions and study the physical properties in different sectors of the phase diagram. A careful finite-size scaling analysis leads to results which give evidence in favor of a scenario with two quantum critical points and an intermediate spontaneously dimerized phase. Our results indicate that the phase transitions are continuous. Using a scaling ansatz we are able to read off critical exponents at the first critical point. In contrast to a bosonization approach, we do not find Ising critical exponents. We show that the low-energy physics of the strong-coupling phase can only partly be understood in terms of the strong-coupling behavior of the ordinary Hubbard model.
Density matrix renormalization group methods are used to investigate the quantum phase diagram of a one-dimensional half-filled ionic Peierls-Hubbard model at the antiadiabatic limit where quantum phonon fluctuations are taken into account partially. We found that two continuous phase transitions always exist from dimerized spin-gapped (bond-order-wave) state to band-insulator and undimerized spin-gapless (Mott-insulator) phase while undimerized spin-gapless phase vanishes at the adiabatic limit. Our results indicate that quantum phonon fluctuations, electron-electron interaction, and ionic potential combine in the formation of the bond-order wave phase.
We investigate the ground-state phase diagram of the one-dimensional half-filled Hubbard model with an alternating potential---a model for the charge-transfer organic materials and the ferroelectric perovskites. We numerically determine the global phase diagram of this model using the level-crossing and the phenomenological renormalization-group methods based on the exact diagonalization calculations. Our results support the mechanism of the double phase transitions between Mott and band insulators pointed out by Fabrizio, Gogolin, and Nersesyan [Phys. Rev. Lett. 83, 2014 (1999)]: We confirm the existence of the spontaneously dimerized phase as an intermediate state. Further we provide numerical evidence to check the criticalities on the phase boundaries. Especially, we perform the finite-size-scaling analysis of the excitation gap to show the two-dimensional Ising transition in the charge part. On the other hand, we confirm that the dimerized phase survives in the strong-coupling limit, which is one of the resultants of competition between the ionicity and correlation effects.
We have studied the neutral-ionic transition in organic mixed-stack compounds. A unified model has been derived which, in limiting cases, is equivalent to the models proposed earlier, the donor-acceptor model, and the ionic Hubbard model. Detailed numerical calculations have been performed on this unified model with the help of the density-matrix renormalization-group (DMRG) procedure calculating excitation gaps, ionicity, lattice site entropy, two-site entropy, and the dimer order parameter on long chains and the unified phase diagram has been determined.