Anomalous dynamical line shapes in a quantum magnet at finite temperature

The effect of thermal fluctuations on the dynamics of a gapped quantum magnet is studied using inelastic neutron scattering on copper nitrate, a model material for the spin-1/2, one-dimensional (1D) bond alternating Heisenberg chain. A large, highly deuterated, single-crystal sample of copper nitrat...

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Main Authors: Tennant, D, Lake, B, James, A, Essler, F, Notbohm, S, Mikeska, H, Fielden, J, Koegerler, P, Canfield, P, Telling, M
Format: Journal article
Language:English
Published: 2012
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author Tennant, D
Lake, B
James, A
Essler, F
Notbohm, S
Mikeska, H
Fielden, J
Koegerler, P
Canfield, P
Telling, M
author_facet Tennant, D
Lake, B
James, A
Essler, F
Notbohm, S
Mikeska, H
Fielden, J
Koegerler, P
Canfield, P
Telling, M
author_sort Tennant, D
collection OXFORD
description The effect of thermal fluctuations on the dynamics of a gapped quantum magnet is studied using inelastic neutron scattering on copper nitrate, a model material for the spin-1/2, one-dimensional (1D) bond alternating Heisenberg chain. A large, highly deuterated, single-crystal sample of copper nitrate is produced using a solution growth method and measurements are made using the high-resolution backscattering spectrometer OSIRIS at the ISIS Facility. Theoretical calculations and numerical analysis are combined to interpret the physical origin of the thermal effects observed in the magnetic spectra. The primary observations are (1) a thermally induced central peak due to intraband scattering, which is similar to Villain scattering familiar from soliton systems in 1D, and (2) the one-magnon quasiparticle pole is seen to develop with temperature into an asymmetric continuum of scattering. We relate this asymmetric line broadening to a thermal strongly correlated state caused by hard-core constraints and quasiparticle interactions. These findings are a counter example to recent assertions of the universality of line broadening in 1D systems and are applicable to a broad range of quantum systems. © 2012 American Physical Society.
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spelling oxford-uuid:70682ad4-1e03-40db-ba7c-7d1f2bc3e18c2022-03-26T19:36:59ZAnomalous dynamical line shapes in a quantum magnet at finite temperatureJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:70682ad4-1e03-40db-ba7c-7d1f2bc3e18cEnglishSymplectic Elements at Oxford2012Tennant, DLake, BJames, AEssler, FNotbohm, SMikeska, HFielden, JKoegerler, PCanfield, PTelling, MThe effect of thermal fluctuations on the dynamics of a gapped quantum magnet is studied using inelastic neutron scattering on copper nitrate, a model material for the spin-1/2, one-dimensional (1D) bond alternating Heisenberg chain. A large, highly deuterated, single-crystal sample of copper nitrate is produced using a solution growth method and measurements are made using the high-resolution backscattering spectrometer OSIRIS at the ISIS Facility. Theoretical calculations and numerical analysis are combined to interpret the physical origin of the thermal effects observed in the magnetic spectra. The primary observations are (1) a thermally induced central peak due to intraband scattering, which is similar to Villain scattering familiar from soliton systems in 1D, and (2) the one-magnon quasiparticle pole is seen to develop with temperature into an asymmetric continuum of scattering. We relate this asymmetric line broadening to a thermal strongly correlated state caused by hard-core constraints and quasiparticle interactions. These findings are a counter example to recent assertions of the universality of line broadening in 1D systems and are applicable to a broad range of quantum systems. © 2012 American Physical Society.
spellingShingle Tennant, D
Lake, B
James, A
Essler, F
Notbohm, S
Mikeska, H
Fielden, J
Koegerler, P
Canfield, P
Telling, M
Anomalous dynamical line shapes in a quantum magnet at finite temperature
title Anomalous dynamical line shapes in a quantum magnet at finite temperature
title_full Anomalous dynamical line shapes in a quantum magnet at finite temperature
title_fullStr Anomalous dynamical line shapes in a quantum magnet at finite temperature
title_full_unstemmed Anomalous dynamical line shapes in a quantum magnet at finite temperature
title_short Anomalous dynamical line shapes in a quantum magnet at finite temperature
title_sort anomalous dynamical line shapes in a quantum magnet at finite temperature
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