Polaronic discontinuities induced by off-diagonal coupling

In this paper, we study a form of the Holstein molecular crystal model in which the influence of lattice vibrations on the transfers of electronic excitations between neighboring sites (off-diagonal coupling) is taken into account. Using the Toyozawa Ansatz and the Lanczos algorithm, the Holstein Ha...

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Main Authors: Zhang, Yuyu, Chen, Qing-Hu, Zhao, Yang, Duan, Liwei
Other Authors: School of Materials Science & Engineering
Format: Article
Language:English
Published: 2013
Online Access:https://hdl.handle.net/10356/95038
http://hdl.handle.net/10220/9396
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-950382023-07-14T15:46:37Z Polaronic discontinuities induced by off-diagonal coupling Zhang, Yuyu Chen, Qing-Hu Zhao, Yang Duan, Liwei School of Materials Science & Engineering In this paper, we study a form of the Holstein molecular crystal model in which the influence of lattice vibrations on the transfers of electronic excitations between neighboring sites (off-diagonal coupling) is taken into account. Using the Toyozawa Ansatz and the Lanczos algorithm, the Holstein Hamiltonian with two types of off-diagonal coupling is studied focusing on a number of analyticity issues in the ground state. For finite-sized lattices and antisymmetric coupling, a sequence of discontinuities are found in the polaron energy dispersion, the size of the ground-state phonon cloud, and the linearized von Neumann entropy used to quantify the quantum entanglement between the exciton and the phonons in the ground state. Such behavior is accompanied by a shift of the ground-state crystal momentum from zero to nonzero values as the coupling strength is increased. In the thermodynamic limit, all discontinuities associated with antisymmetric coupling vanish except the one corresponding to the initial departure of the ground-state wavevector from the Brillouin zone center. For the case of symmetric off-diagonal coupling, a smooth crossover is found to exist in all parameters regimes. Published version 2013-03-13T08:06:33Z 2019-12-06T19:07:01Z 2013-03-13T08:06:33Z 2019-12-06T19:07:01Z 2012 2012 Journal Article Zhang, Y., Duan, L., Chen, Q., & Zhao, Y. (2012). Polaronic discontinuities induced by off-diagonal coupling. The Journal of Chemical Physics, 137(3), 034108-. 0021-9606 https://hdl.handle.net/10356/95038 http://hdl.handle.net/10220/9396 10.1063/1.4733986 en The Journal of Chemical Physics © 2012 American Institute of Physics. This paper was published in The Journal of Chemical Physics and is made available as an electronic reprint (preprint) with permission of American Institute of Physics. The paper can be found at the following official DOI: [http://dx.doi.org/10.1063/1.4733986]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law. application/pdf
institution Nanyang Technological University
building NTU Library
continent Asia
country Singapore
Singapore
content_provider NTU Library
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language English
description In this paper, we study a form of the Holstein molecular crystal model in which the influence of lattice vibrations on the transfers of electronic excitations between neighboring sites (off-diagonal coupling) is taken into account. Using the Toyozawa Ansatz and the Lanczos algorithm, the Holstein Hamiltonian with two types of off-diagonal coupling is studied focusing on a number of analyticity issues in the ground state. For finite-sized lattices and antisymmetric coupling, a sequence of discontinuities are found in the polaron energy dispersion, the size of the ground-state phonon cloud, and the linearized von Neumann entropy used to quantify the quantum entanglement between the exciton and the phonons in the ground state. Such behavior is accompanied by a shift of the ground-state crystal momentum from zero to nonzero values as the coupling strength is increased. In the thermodynamic limit, all discontinuities associated with antisymmetric coupling vanish except the one corresponding to the initial departure of the ground-state wavevector from the Brillouin zone center. For the case of symmetric off-diagonal coupling, a smooth crossover is found to exist in all parameters regimes.
author2 School of Materials Science & Engineering
author_facet School of Materials Science & Engineering
Zhang, Yuyu
Chen, Qing-Hu
Zhao, Yang
Duan, Liwei
format Article
author Zhang, Yuyu
Chen, Qing-Hu
Zhao, Yang
Duan, Liwei
spellingShingle Zhang, Yuyu
Chen, Qing-Hu
Zhao, Yang
Duan, Liwei
Polaronic discontinuities induced by off-diagonal coupling
author_sort Zhang, Yuyu
title Polaronic discontinuities induced by off-diagonal coupling
title_short Polaronic discontinuities induced by off-diagonal coupling
title_full Polaronic discontinuities induced by off-diagonal coupling
title_fullStr Polaronic discontinuities induced by off-diagonal coupling
title_full_unstemmed Polaronic discontinuities induced by off-diagonal coupling
title_sort polaronic discontinuities induced by off-diagonal coupling
publishDate 2013
url https://hdl.handle.net/10356/95038
http://hdl.handle.net/10220/9396
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