Quantized lattice dynamic effects on the spin-Peierls transition

The density-matrix renormalization-group method is used to investigate the spin-Peierls transition for Heisenberg spins coupled to quantized phonons. We use a phonon spectrum that interpolates between a gapped, dispersionless (Einstein) limit to a gapless, dispersive (Debye) limit. A variety of theo...

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Main Authors: Pearson, C, Barford, W, Bursill, R
Format: Journal article
Language:English
Published: 2010
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author Pearson, C
Barford, W
Bursill, R
author_facet Pearson, C
Barford, W
Bursill, R
author_sort Pearson, C
collection OXFORD
description The density-matrix renormalization-group method is used to investigate the spin-Peierls transition for Heisenberg spins coupled to quantized phonons. We use a phonon spectrum that interpolates between a gapped, dispersionless (Einstein) limit to a gapless, dispersive (Debye) limit. A variety of theoretical probes are used to determine the quantum phase transition, including energy gap crossing, a finite-size scaling analysis, bond-order autocorrelation functions, and bipartite quantum entanglement. All these probes indicate that in the antiadiabatic phonon limit a quantum phase transition of the Berezinskii-Kosterlitz-Thouless type is observed at a nonzero spin-phonon coupling, gc. An extrapolation from the Einstein limit to the Debye limit is accompanied by an increase in gc for a fixed optical (q=π) phonon gap. We therefore conclude that the dimerized ground state is more unstable with respect to Debye phonons with the introduction of phonon-dispersion renormalizing the effective spin-lattice coupling for the Peierls-active mode. We also show that the staggered spin-spin and phonon displacement order parameters are unreliable means of determining the transition. © 2010 The American Physical Society.
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spelling oxford-uuid:80bbe94d-becd-4e44-912f-71281ad7169f2022-03-26T21:25:20ZQuantized lattice dynamic effects on the spin-Peierls transitionJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:80bbe94d-becd-4e44-912f-71281ad7169fEnglishSymplectic Elements at Oxford2010Pearson, CBarford, WBursill, RThe density-matrix renormalization-group method is used to investigate the spin-Peierls transition for Heisenberg spins coupled to quantized phonons. We use a phonon spectrum that interpolates between a gapped, dispersionless (Einstein) limit to a gapless, dispersive (Debye) limit. A variety of theoretical probes are used to determine the quantum phase transition, including energy gap crossing, a finite-size scaling analysis, bond-order autocorrelation functions, and bipartite quantum entanglement. All these probes indicate that in the antiadiabatic phonon limit a quantum phase transition of the Berezinskii-Kosterlitz-Thouless type is observed at a nonzero spin-phonon coupling, gc. An extrapolation from the Einstein limit to the Debye limit is accompanied by an increase in gc for a fixed optical (q=π) phonon gap. We therefore conclude that the dimerized ground state is more unstable with respect to Debye phonons with the introduction of phonon-dispersion renormalizing the effective spin-lattice coupling for the Peierls-active mode. We also show that the staggered spin-spin and phonon displacement order parameters are unreliable means of determining the transition. © 2010 The American Physical Society.
spellingShingle Pearson, C
Barford, W
Bursill, R
Quantized lattice dynamic effects on the spin-Peierls transition
title Quantized lattice dynamic effects on the spin-Peierls transition
title_full Quantized lattice dynamic effects on the spin-Peierls transition
title_fullStr Quantized lattice dynamic effects on the spin-Peierls transition
title_full_unstemmed Quantized lattice dynamic effects on the spin-Peierls transition
title_short Quantized lattice dynamic effects on the spin-Peierls transition
title_sort quantized lattice dynamic effects on the spin peierls transition
work_keys_str_mv AT pearsonc quantizedlatticedynamiceffectsonthespinpeierlstransition
AT barfordw quantizedlatticedynamiceffectsonthespinpeierlstransition
AT bursillr quantizedlatticedynamiceffectsonthespinpeierlstransition