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

arXiv:cond-mat/0006426 · Physical Review Letters

Energy Separation of Single-Particle and Continuum States in an S=1/2 Weakly Coupled Chains Antiferromagnet

A. Zheludev, M. Kenzelmann, S. Raymond, E. Ressouche, Takatsugu Masuda, Kazuhisa Kakurai, Sergei Maslov, I. Tsukada, K. Uchinokura, Andrew R. Wildes

Published Nov 27, 2000• 54 citations
arXivHTMLPDF

Abstract

Inelastic neutron scattering is used to study transverse-polarized magnetic excitations in the quasi-one-dimensional $S\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1/2$ antiferromagnet ${\mathrm{BaCu}}_{2}{\mathrm{Si}}_{2}{\mathrm{O}}_{7}$, where the saturation value for the N\'eel order parameter is ${m}_{0}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.12{\ensuremath{\mu}}_{\mathrm{B}}$ per spin. At low energies the spectrum is totally dominated by resolution-limited spin-wave-like excitations. An excitation continuum sets in above a well-defined threshold frequency. Experimental results are discussed in the context of current theories for weakly interacting quantum half-integer-spin chains.

DOI
10.1103/physrevlett.85.4799

Related papers

Spin dynamics in the $S=1/2$ weakly-coupled chains antiferromagnet BaCu$_2$Si$_2$O$_7$

A. Zheludev, M. Kenzelmann, S. Raymond +3 more

Inelastic neutron scattering is used to identify single-particle and continuum spin excitations in the quasi-one-dimensional $S=1/2$ antiferromagnet \ba. In the data analysis, close attention is given to resolution effects. A gap in the continuum spectrum at $Δ_c=4.74.8$ meV is directly observed. The gap energy is in excellent agreement with existing theoretical predictions. Below the gap, the spectrum is dominated by sharp accoustic spin wave excitations.

arXiv:cond-mat/0105223•May 10, 2001•1 citation

Dominance of the Excitation Continuum in the Longitudinal Spectrum of Weakly Coupled Heisenberg S=1/2 Chains

A. Zheludev, Kazuhisa Kakurai, Takatsugu Masuda +2 more

A low-field spin-flop transition in the quasi-one-dimensional antiferromagnet $\mathrm{B}\mathrm{a}\mathrm{C}{\mathrm{u}}_{\mathrm{2}}\mathrm{S}{\mathrm{i}}_{\mathrm{2}}{\mathrm{O}}_{\mathrm{7}}$ is exploited to study the polarization dependence of low-energy magnetic excitations. The measured longitudinal spectrum is best described as a single broad continuum, with no sharp ``longitudinal mode,'' in apparent contradiction with the commonly used chain-mean-field and random phase approximation (MF/RPA) theories. The observed behavior is also quite different than that previously seen in the related $\mathrm{K}\mathrm{C}\mathrm{u}{\mathrm{F}}_{\mathrm{3}}$ material, presumably due to a large difference in the relative strength of interchain interactions. The results highlight the limitations of the chain-MF/RPA approach.

arXiv:cond-mat/0210568•Physical Review Letters•Oct 22, 2002•29 citations

Evidence for magnetic quasiparticle phase separation in a quasi-one-dimensional quantum magnet

L. Shen, E. Campillo, O. Zaharko +6 more

Magnetic systems composed of weakly coupled spin-1/2 chains are fertile ground for hosting the fractional magnetic excitations that are intrinsic to interacting fermions in one-dimension (1D). However, the exotic physics arising from the quantum many-body interactions beyond 1D are poorly understood in materials of this class. Spinons and psinons are two mutually exclusive low-energy magnetic quasiparticles; the excitation seen depends on the ground state of the spin chain. Here, we present inelastic neutron scattering and neutron diffraction evidence for their coexistence in SrCo$_{2}$V$_{2}$O$_{8}$ at milli-Kelvin temperatures in part of the N\'eel phase (2.4 T $\leq$ $\mu_\mathrm{{0}}$H $<$ 3.9 T) and possibly also the field-induced spin density wave phase up to the highest field probed ($\mu_\mathrm{{0}}$H $\geq$ 3.9 T, $\mu_\mathrm{{0}}$H$_\mathbf{\mathrm{{max}}}$ = 5.5 T). These results unveil a novel spatial phase inhomogeneity for the weakly coupled spin chains in this compound. This quantum dynamical phase separation is a new phenomenon in quasi-1D quantum magnets, highlighting the non-trivial consequences of inter-chain coupling.

•Sep 6, 2019•0 citations

Continuum in the Spin-Excitation Spectrum of a Haldane Chain Observed by Neutron Scattering in CsNiCl3

Igor A. Zaliznyak, S.-H. Lee, S. V. Petrov

The spin-excitation continuum, expected to dominate the low-energy fluctuation spectrum in the Haldane spin chain around the Brillouin zone center, $q\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0$, is directly observed by inelastic magnetic neutron scattering in the $S\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1$ quasi-1D antiferromagnet ${\mathrm{CsNiCl}}_{3}$. We find that the single mode approximation fails, and that a finite energy width appears in the dynamic correlation function $S(q,\ensuremath{\omega})$ for $q\ensuremath{\lesssim}0.5\ensuremath{\pi}$. The width increases with decreasing $q$, while $S(q,\ensuremath{\omega})$ acquires an asymmetric shape qualitatively similar to that predicted for the two-magnon continuum in the nonlinear $\ensuremath{\sigma}$-model.

arXiv:cond-mat/0010049•Physical Review Letters•Jun 15, 2001•73 citations

Continuum spin excitations in S=1 one-dimensional antiferromagnet

Igor A. Zaliznyak

We present detailed measurement of the nonhydrodynamic part of the spin excitation spectrum in the model quasi-one-dimensional S=1 antiferromagnet CsNiCl3 by inelastic magnetic neutron scattering. In the better part of the Brillouin zone the effect of interchain coupling is negligible, and the spin dynamics reflects that of a single Haldane chain. We find that at q≲0.6π this quantum spin system ceases to support coherent propagating excitation, which gradually turns into a continuum band of states, whose width grows with decreasing q. This finding is consistently verified under different resolution conditions, obtained with two different high-luminosity experimental setups.

arXiv:cond-mat/0109065•Journal of Applied Physics•May 15, 2002•6 citations

Measurement of the spin-excitation continuum in one-dimensional KCuF3 using neutron scattering

D. M. Tennant, Roger Arthur Cowley, S. E. Nagler +1 more

In this, and the following paper, we present the results of a detailed experimental investigation into the spin dynamics of the quasi-one-dimensional S=1/2 Heisenberg antiferromagnet ${\mathrm{KCuF}}_{3}$. In this paper we report results of inelastic neutron-scattering measurements made using the MARI time-of-flight spectrometer at the Rutherford Appleton Laboratory. Measurement of the magnetic excitation spectrum was made in both the low-temperature phase, where the chains are ordered together, and in the high-temperature phase, where the correlations between chains become unimportant. We compare our measurements with the M\"uller ansatz, which is identified with a two-spinon cross section, and find excellent agreement with this. The effect of temperature on the excitation continuum was also investigated. A series of measurements were made at temperatures ranging from 20 to 200 K. These results are compared to the predictions of field theory for the one-dimensional Heisenberg chain. Again good agreement is found with the theoretical predictions. In the following paper measurements of the low-energy scattering in the ordered phase, made on a triple-axis spectrometer, are presented.

Physical review. B, Condensed matter•Nov 1, 1995•157 citations
Inelastic neutron scattering is used to study transverse-polarized magnetic excitations in the quasi-one-dimensional S=1/2S\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1/2S=1/2 antiferromagnet BaCu2Si2O7{\mathrm{BaCu}}_{2}{\mathrm{Si}}_{2}{\mathrm{O}}_{7}BaCu2​Si2​O7​, where the saturation value for the N'eel order parameter is m0=0.12\ensuremathμB{m}_{0}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0.12{\ensuremath{\mu}}_{\mathrm{B}}m0​=0.12\ensuremathμB​ per spin. At low energies the spectrum is totally dominated by resolution-limited spin-wave-like excitations. An excitation continuum sets in above a well-defined threshold frequency. Experimental results are discussed in the context of current theories for weakly interacting quantum half-integer-spin chains.
Spin dynamics in the S=1/2S=1/2S=1/2 weakly-coupled chains antiferromagnet BaCu2_22​Si2_22​O7_77​
Inelastic neutron scattering is used to identify single-particle and continuum spin excitations in the quasi-one-dimensional S=1/2S=1/2S=1/2 antiferromagnet \ba. In the data analysis, close attention is given to resolution effects. A gap in the continuum spectrum at Δc=4.74.8Δ_c=4.74.8Δc​=4.74.8 meV is directly observed. The gap energy is in excellent agreement with existing theoretical predictions. Below the gap, the spectrum is dominated by sharp accoustic spin wave excitations.
A low-field spin-flop transition in the quasi-one-dimensional antiferromagnet BaCu2Si2O7\mathrm{B}\mathrm{a}\mathrm{C}{\mathrm{u}}_{\mathrm{2}}\mathrm{S}{\mathrm{i}}_{\mathrm{2}}{\mathrm{O}}_{\mathrm{7}}BaCu2​Si2​O7​ is exploited to study the polarization dependence of low-energy magnetic excitations. The measured longitudinal spectrum is best described as a single broad continuum, with no sharp ``longitudinal mode,'' in apparent contradiction with the commonly used chain-mean-field and random phase approximation (MF/RPA) theories. The observed behavior is also quite different than that previously seen in the related KCuF3\mathrm{K}\mathrm{C}\mathrm{u}{\mathrm{F}}_{\mathrm{3}}KCuF3​ material, presumably due to a large difference in the relative strength of interchain interactions. The results highlight the limitations of the chain-MF/RPA approach.
Magnetic systems composed of weakly coupled spin-1/2 chains are fertile ground for hosting the fractional magnetic excitations that are intrinsic to interacting fermions in one-dimension (1D). However, the exotic physics arising from the quantum many-body interactions beyond 1D are poorly understood in materials of this class. Spinons and psinons are two mutually exclusive low-energy magnetic quasiparticles; the excitation seen depends on the ground state of the spin chain. Here, we present inelastic neutron scattering and neutron diffraction evidence for their coexistence in SrCo2_{2}2​V2_{2}2​O8_{8}8​ at milli-Kelvin temperatures in part of the N\'eel phase (2.4 T ≤\leq≤ μ0\mu_\mathrm{{0}}μ0​H <<< 3.9 T) and possibly also the field-induced spin density wave phase up to the highest field probed (μ0\mu_\mathrm{{0}}μ0​H ≥\geq≥ 3.9 T, μ0\mu_\mathrm{{0}}μ0​Hmax_\mathbf{\mathrm{{max}}}max​ = 5.5 T). These results unveil a novel spatial phase inhomogeneity for the weakly coupled spin chains in this compound. This quantum dynamical phase separation is a new phenomenon in quasi-1D quantum magnets, highlighting the non-trivial consequences of inter-chain coupling.
The spin-excitation continuum, expected to dominate the low-energy fluctuation spectrum in the Haldane spin chain around the Brillouin zone center, q=0q\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}0q=0, is directly observed by inelastic magnetic neutron scattering in the S=1S\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}1S=1 quasi-1D antiferromagnet CsNiCl3{\mathrm{CsNiCl}}_{3}CsNiCl3​. We find that the single mode approximation fails, and that a finite energy width appears in the dynamic correlation function $S(q,\ensuremath{\omega})$ for $q\ensuremath{\lesssim}0.5\ensuremath{\pi}$. The width increases with decreasing qqq, while $S(q,\ensuremath{\omega})$ acquires an asymmetric shape qualitatively similar to that predicted for the two-magnon continuum in the nonlinear $\ensuremath{\sigma}$-model.
We present detailed measurement of the nonhydrodynamic part of the spin excitation spectrum in the model quasi-one-dimensional S=1 antiferromagnet CsNiCl3 by inelastic magnetic neutron scattering. In the better part of the Brillouin zone the effect of interchain coupling is negligible, and the spin dynamics reflects that of a single Haldane chain. We find that at q≲0.6π this quantum spin system ceases to support coherent propagating excitation, which gradually turns into a continuum band of states, whose width grows with decreasing q. This finding is consistently verified under different resolution conditions, obtained with two different high-luminosity experimental setups.
In this, and the following paper, we present the results of a detailed experimental investigation into the spin dynamics of the quasi-one-dimensional S=1/2 Heisenberg antiferromagnet KCuF3{\mathrm{KCuF}}_{3}KCuF3​. In this paper we report results of inelastic neutron-scattering measurements made using the MARI time-of-flight spectrometer at the Rutherford Appleton Laboratory. Measurement of the magnetic excitation spectrum was made in both the low-temperature phase, where the chains are ordered together, and in the high-temperature phase, where the correlations between chains become unimportant. We compare our measurements with the M\"uller ansatz, which is identified with a two-spinon cross section, and find excellent agreement with this. The effect of temperature on the excitation continuum was also investigated. A series of measurements were made at temperatures ranging from 20 to 200 K. These results are compared to the predictions of field theory for the one-dimensional Heisenberg chain. Again good agreement is found with the theoretical predictions. In the following paper measurements of the low-energy scattering in the ordered phase, made on a triple-axis spectrometer, are presented.