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./Physical review. B

Antiferromagnetic resonance and two-magnon absorption in an XXZ-chain antiferromagnet Cs 2 CoCl 4

T. A. Soldatov, A. I. Smirnov

Published Nov 17, 2025• 1 citation
Publisher

Abstract

Magnetic excitations of the exchange-dipole quasi-one-dimensional XXZ antiferromagnet are studied in the ordered phase. We observe a transformation of the electron spin resonance (ESR) spectrum when crossing the N\'eel temperature near 0.2 K. The single-mode ESR of a correlated XXZ chain transforms in the multimode spectrum in the ordered phase. The multimode spectrum consists mainly of the intensive mode of a single correlated chain, which is surrounded and/or indented by numerous weak satellites. The number of securely fixed modes is eight at $\mathbf{H}\ensuremath{\parallel}b$ and twelve at $\mathbf{H}\ensuremath{\parallel}a$. In addition to the multimode resonance observed at the transverse polarization of the microwave and static magnetic fields, we reveal a wide band of absorption by ($k$,--$k$) pairs of quasiparticles at the longitudinal polarization. This kind of absorption of microwaves occurs both in the ordered and specific spin-liquid phases, revealing the presence of quasiparticles in the specific spin-liquid phase.

DOI
10.1103/ynvv-tszv

Related papers

Unusual magnetic excitations in the weakly ordered spin- 12 chain antiferromagnet Sr2CuO3 : Possible evidence for Goldstone magnon coupled with the amplitude mode

Elena Sergeicheva, Sergei S. Sosin, L. A. Prozorova +2 more

We report on an electron spin resonance (ESR) study of a nearly one-dimensional (1D) spin-$\frac{1}{2}$ chain antiferromagnet, ${\mathrm{Sr}}_{2}{\mathrm{CuO}}_{3}$, with extremely weak magnetic ordering. The ESR spectra at $T>{T}_{N}$, in the disordered Luttinger-spin-liquid phase, reveal nearly ideal Heisenberg-chain behavior with only a very small, field-independent linewidth, $\ensuremath{\sim}1/T$. In the ordered state, below ${T}_{N}$, we identify field-dependent antiferromagnetic resonance modes, which are well described by pseudo-Goldstone magnons in the model of a collinear biaxial antiferromagnet. Additionally, we observe a major resonant mode with unusual and strongly anisotropic properties, which is not anticipated by the conventional theory of Goldstone spin waves. We propose that this unexpected magnetic excitation can be attributed to a field-independent magnon mode renormalized due to its interaction with the high-energy amplitude (Higgs) mode in the regime of weak spontaneous symmetry breaking.

Physical review. B./Physical review. B•Jan 18, 2017•12 citations

Fermi liquid of spinons in quasi-one-dimensional antiferromagnets

Aleksandr I. Smirnov

We report the experimental observation of a shift of the boundaries of the spinon continuum caused by a Fermiliquid interaction of spinons in the spin-liquid S 1a2 chaintype antiferromagnet K 2 CuSO 4 Br 2 .The parameter of spinon interaction, which determines the probability of backscattering, is found.In the pseudospin S 1a2 chain-type strongly anisotropic antiferromagnet Cs 2 CoCl 4 , a shift in the magnetic resonance frequency is detected during the crossover from the disordered spin regime to the state of correlated XXZ-type spin chains at a temperature above the emergence of longrange antiferromagnetic order.This resonance shift is explained on the basis of the spectrum of spin excitations in correlated XXZ chains and corresponds to theoretical simulation of the spectra of spinon-type magnetic fluctuations in XXZ chains [P.Laurell et al.Phys.Rev. Lett.127 037201 (2021)].

Physics-Uspekhi•Dec 1, 2024•3 citations

Magnetic Excitation in the S = 1/2 Ising-like Antiferromagnetic Chain CsCoCl3 in Longitudinal Magnetic Fields Studied by High-field ESR Measurements

Shojiro Kimura, Hiroaki Onishi, Kouichi Okunishi +5 more

High-field electron spin resonance (ESR) measurements were performed on the S = 1/2 Ising-like antiferromagnetic chain CsCoCl3 in the frequency range up to 4.4 THz and magnetic fields for H || c up to 53 T. We observed softening of the spinon excitation, which drives the spin chain into the quantum critical state at the critical field Hc = 33.0 T. Above Hc, we observed the string excitation at the wave number q = π, which is characteristic of the S = 1/2 spin chain in the quantum critical state in the magnetic fields. We also observed a crossover of the string excitation to the magnon bound state above the saturation field Hs = 43.9 T upon increasing the magnetic fields. Finally, we discuss how the string excitation and magnon bound state can be excited by the electric dipole transition due to spin quadrupolar resonance.

Journal of the Physical Society of Japan•Jul 28, 2023•5 citations

Dynamics of field-induced phases in spin-1 antifferomagnetic chains

Christina Psaroudaki

This thesis is devoted to the study of a class of antifferomagnetic spin–1 chains with astrong easy plane anisotropy in the presence of magnetic field H. At zero temperature thesystem undergoes two quantum phase transitions at critical fields H1 and H2. Reliableand detailed theoretical analysis is provided on the Electron Spin Resonance (ESR)spectrum, thermodynamics and the thermal transport of the model. The tools at handrange from exact analytical solutions and to numerical simulation techniques. The S = 1antiferromagnet in a magnetic field can be systematically mapped onto an S = 1/2XXZ chain in a longitudinal magnetic field. This effective S = 1/2 description has beenextensively used in order to gain a better physical understanding of the original S = 1chain.For the Electron Spin Resonance spectrum, apart from the theoretical analysis, high-field ESR experimental studies of the compound N iCl2 − 4SC(NH2)2 (abbreviatedas DTN) are presented and found consistent with theoretical predictions. The mostinteresting feature is the experimental signature of the single–ion two–magnon boundstate.Part of this thesis is devoted to the magnetic–field and temperature dependence ofmagnetization and specific heat for the whole field–region and a wide range of temperatures,with special emphasis at the critical behaviour of these quantities at the criticalfields. Finally, the calculation of dynamic correlation functions pertinent to the studyof thermal transport is addressed for the S = 1 model with easy plane anisotropy andthe S = 1/2 XXZ model in the presence of finite magnetic field.

•Dec 1, 2014•0 citations

Neutron Scattering Studies of Excitations in Spin Chains

E. Hirtenlechner

Many phenomena in magnetism can be described using classical models, yet magnetism is a quantum mechanical effect. In addition to thermal fluctuations, quantum fluctuations arise due to the quantum uncertainty of the ground state. These fluctuations are enhanced by low dimensionality and low spin. Spin chains show interesting excitations associated with quasiparticles. Model materials for spin chains can be realized in compounds where the interchain interactions are weak enough. This thesis presents neutron scattering studies of two model materials for spin chains with different spin symmetry. The spin2 Heisenberg antiferromagnetic chain CuSO4*5D2O has a main exchange of J ∼ 3 K, which permits to study its excitation spectrum up to temperatures of ten times the exchange. The spin2 Heisenberg magnet has been studied widely both theoretically and experimentally. The excitation spectrum of the spin2 Heisenberg antiferromagnet consists of quasiparticles called spinons, and calculations for it exist for T = 0 and as a function of temperature. A quantitative comparison between experimental data and theoretical models across a range of temperatures is presented. The excitation spectrum of CuSO4*5D2O is excellently described by the excitation spectrum of a spin2 Heisenberg antiferromagnetic chain at finite temperatures. Energy-temperature scaling is observed at temperatures up to 2J . For these temperatures the Luttinger liquid description of the spin2 Heisenberg antiferromagnetic chain is valid. A spinon continuum is confirmed at all measured temperatures. Therefore, even at ten times the main exchange (T ≈ 10 J), CuSO4*5D2O shows the behavior of a quantum magnet, and not of a classical system at infinite temperatures, for which one would expect single spin flips. The Ising chain is one of the most studied models in magnetism, one model compound for it is RbCoCl3. Optical spectroscopy measurements suggest a lower gap than for similar compounds, which makes it better suited for high resolution neutron spectroscopy. Magnetic correlations along the chains arise in RbCoCl3 below 80 K. A gapped continuum is observed, which arises from isolated antiferromagnetic Ising chains. Below the first magnetic ordering temperature TN1 ≈ 28 K bound states are observed, which arise due to correlations which form between the chains. Strong diffuse scattering leads to the conclusion that disorder is still present. At the second magnetic ordering transition, at TN2 ≈ 14 K, the bound states split as the correlations between the chains change. Fits indicate that the correlations change continuously as a function of temperature. Above TN2 the excitation spectrum of RbCoCl3 can be described by a spin1 2 Ising chain with an XY-component which is treated as a perturbation. Below TN2 the main features are reproduced correctly, but deviations from the details indicate that additional terms in the Hamiltonian may be necessary. This thesis was carried out at the Institut Laue-Langevin, the Laboratory for Neutron Scattering and Imaging at the Paul Scherrer Institute and ETH Zurich.

•Jan 1, 2014•0 citations

Unexpected magnetic phase in the weakly ordered spin- 12 chain cuprate Sr2CuO3

E. G. Sergeicheva, S. S. Sosin, D. I. Gorbunov +3 more

The magnetic phase diagram of a spin-$\frac{1}{2}$ chain antiferromagnet ${\mathrm{Sr}}_{2}{\mathrm{CuO}}_{3}$ is studied by an ultrasound phase-sensitive detection technique. The system is in the extreme proximity of the Luttinger-liquid quantum-critical point and we observe an unusually strong effect of magnetic field, which is very weak compared to the in-chain interaction, on the N\'eel ordering temperature. Inside the ordered phase, we detect an unexpected, field-induced continuous phase transition. The transition is accompanied by softening of magnetic excitation observed by electron-spin resonance, which in previous work [E. G. Sergeicheva et al., Phys. Rev. B 95, 020411(R) (2017)] was associated with a longitudinal (amplitude) mode of the order parameter. These results suggest a transition from a transverse collinear antiferromagnet to an amplitude-modulated spin-density-wave phase in a very weak magnetic field, which is unexpected for a system of weakly coupled Heisenberg spin-$\frac{1}{2}$ chains.

arXiv:1911.07592•Physical review. B./Physical review. B•May 15, 2020•3 citations
Magnetic excitations of the exchange-dipole quasi-one-dimensional XXZ antiferromagnet are studied in the ordered phase. We observe a transformation of the electron spin resonance (ESR) spectrum when crossing the N'eel temperature near 0.2 K. The single-mode ESR of a correlated XXZ chain transforms in the multimode spectrum in the ordered phase. The multimode spectrum consists mainly of the intensive mode of a single correlated chain, which is surrounded and/or indented by numerous weak satellites. The number of securely fixed modes is eight at H\ensuremath∥b\mathbf{H}\ensuremath{\parallel}bH\ensuremath∥b and twelve at H\ensuremath∥a\mathbf{H}\ensuremath{\parallel}aH\ensuremath∥a. In addition to the multimode resonance observed at the transverse polarization of the microwave and static magnetic fields, we reveal a wide band of absorption by (kkk,--kkk) pairs of quasiparticles at the longitudinal polarization. This kind of absorption of microwaves occurs both in the ordered and specific spin-liquid phases, revealing the presence of quasiparticles in the specific spin-liquid phase.
We report on an electron spin resonance (ESR) study of a nearly one-dimensional (1D) spin-12\frac{1}{2}21​ chain antiferromagnet, Sr2CuO3{\mathrm{Sr}}_{2}{\mathrm{CuO}}_{3}Sr2​CuO3​, with extremely weak magnetic ordering. The ESR spectra at T>TNT>{T}_{N}T>TN​, in the disordered Luttinger-spin-liquid phase, reveal nearly ideal Heisenberg-chain behavior with only a very small, field-independent linewidth, $\ensuremath{\sim}1/T$. In the ordered state, below TN{T}_{N}TN​, we identify field-dependent antiferromagnetic resonance modes, which are well described by pseudo-Goldstone magnons in the model of a collinear biaxial antiferromagnet. Additionally, we observe a major resonant mode with unusual and strongly anisotropic properties, which is not anticipated by the conventional theory of Goldstone spin waves. We propose that this unexpected magnetic excitation can be attributed to a field-independent magnon mode renormalized due to its interaction with the high-energy amplitude (Higgs) mode in the regime of weak spontaneous symmetry breaking.
We report the experimental observation of a shift of the boundaries of the spinon continuum caused by a Fermiliquid interaction of spinons in the spin-liquid S 1a2 chaintype antiferromagnet K 2 CuSO 4 Br 2 .The parameter of spinon interaction, which determines the probability of backscattering, is found.In the pseudospin S 1a2 chain-type strongly anisotropic antiferromagnet Cs 2 CoCl 4 , a shift in the magnetic resonance frequency is detected during the crossover from the disordered spin regime to the state of correlated XXZ-type spin chains at a temperature above the emergence of longrange antiferromagnetic order.This resonance shift is explained on the basis of the spectrum of spin excitations in correlated XXZ chains and corresponds to theoretical simulation of the spectra of spinon-type magnetic fluctuations in XXZ chains [P.Laurell et al.Phys.Rev. Lett.127 037201 (2021)].
High-field electron spin resonance (ESR) measurements were performed on the S = 1/2 Ising-like antiferromagnetic chain CsCoCl3 in the frequency range up to 4.4 THz and magnetic fields for H || c up to 53 T. We observed softening of the spinon excitation, which drives the spin chain into the quantum critical state at the critical field Hc = 33.0 T. Above Hc, we observed the string excitation at the wave number q = π, which is characteristic of the S = 1/2 spin chain in the quantum critical state in the magnetic fields. We also observed a crossover of the string excitation to the magnon bound state above the saturation field Hs = 43.9 T upon increasing the magnetic fields. Finally, we discuss how the string excitation and magnon bound state can be excited by the electric dipole transition due to spin quadrupolar resonance.
This thesis is devoted to the study of a class of antifferomagnetic spin–1 chains with astrong easy plane anisotropy in the presence of magnetic field H. At zero temperature thesystem undergoes two quantum phase transitions at critical fields H1 and H2. Reliableand detailed theoretical analysis is provided on the Electron Spin Resonance (ESR)spectrum, thermodynamics and the thermal transport of the model. The tools at handrange from exact analytical solutions and to numerical simulation techniques. The S = 1antiferromagnet in a magnetic field can be systematically mapped onto an S = 1/2XXZ chain in a longitudinal magnetic field. This effective S = 1/2 description has beenextensively used in order to gain a better physical understanding of the original S = 1chain.For the Electron Spin Resonance spectrum, apart from the theoretical analysis, high-field ESR experimental studies of the compound N iCl2 − 4SC(NH2)2 (abbreviatedas DTN) are presented and found consistent with theoretical predictions. The mostinteresting feature is the experimental signature of the single–ion two–magnon boundstate.Part of this thesis is devoted to the magnetic–field and temperature dependence ofmagnetization and specific heat for the whole field–region and a wide range of temperatures,with special emphasis at the critical behaviour of these quantities at the criticalfields. Finally, the calculation of dynamic correlation functions pertinent to the studyof thermal transport is addressed for the S = 1 model with easy plane anisotropy andthe S = 1/2 XXZ model in the presence of finite magnetic field.
Many phenomena in magnetism can be described using classical models, yet magnetism is a quantum mechanical effect. In addition to thermal fluctuations, quantum fluctuations arise due to the quantum uncertainty of the ground state. These fluctuations are enhanced by low dimensionality and low spin. Spin chains show interesting excitations associated with quasiparticles. Model materials for spin chains can be realized in compounds where the interchain interactions are weak enough. This thesis presents neutron scattering studies of two model materials for spin chains with different spin symmetry. The spin2 Heisenberg antiferromagnetic chain CuSO4*5D2O has a main exchange of J ∼ 3 K, which permits to study its excitation spectrum up to temperatures of ten times the exchange. The spin2 Heisenberg magnet has been studied widely both theoretically and experimentally. The excitation spectrum of the spin2 Heisenberg antiferromagnet consists of quasiparticles called spinons, and calculations for it exist for T = 0 and as a function of temperature. A quantitative comparison between experimental data and theoretical models across a range of temperatures is presented. The excitation spectrum of CuSO4*5D2O is excellently described by the excitation spectrum of a spin2 Heisenberg antiferromagnetic chain at finite temperatures. Energy-temperature scaling is observed at temperatures up to 2J . For these temperatures the Luttinger liquid description of the spin2 Heisenberg antiferromagnetic chain is valid. A spinon continuum is confirmed at all measured temperatures. Therefore, even at ten times the main exchange (T ≈ 10 J), CuSO4*5D2O shows the behavior of a quantum magnet, and not of a classical system at infinite temperatures, for which one would expect single spin flips. The Ising chain is one of the most studied models in magnetism, one model compound for it is RbCoCl3. Optical spectroscopy measurements suggest a lower gap than for similar compounds, which makes it better suited for high resolution neutron spectroscopy. Magnetic correlations along the chains arise in RbCoCl3 below 80 K. A gapped continuum is observed, which arises from isolated antiferromagnetic Ising chains. Below the first magnetic ordering temperature TN1 ≈ 28 K bound states are observed, which arise due to correlations which form between the chains. Strong diffuse scattering leads to the conclusion that disorder is still present. At the second magnetic ordering transition, at TN2 ≈ 14 K, the bound states split as the correlations between the chains change. Fits indicate that the correlations change continuously as a function of temperature. Above TN2 the excitation spectrum of RbCoCl3 can be described by a spin1 2 Ising chain with an XY-component which is treated as a perturbation. Below TN2 the main features are reproduced correctly, but deviations from the details indicate that additional terms in the Hamiltonian may be necessary. This thesis was carried out at the Institut Laue-Langevin, the Laboratory for Neutron Scattering and Imaging at the Paul Scherrer Institute and ETH Zurich.
The magnetic phase diagram of a spin-12\frac{1}{2}21​ chain antiferromagnet Sr2CuO3{\mathrm{Sr}}_{2}{\mathrm{CuO}}_{3}Sr2​CuO3​ is studied by an ultrasound phase-sensitive detection technique. The system is in the extreme proximity of the Luttinger-liquid quantum-critical point and we observe an unusually strong effect of magnetic field, which is very weak compared to the in-chain interaction, on the N\'eel ordering temperature. Inside the ordered phase, we detect an unexpected, field-induced continuous phase transition. The transition is accompanied by softening of magnetic excitation observed by electron-spin resonance, which in previous work [E. G. Sergeicheva et al., Phys. Rev. B 95, 020411(R) (2017)] was associated with a longitudinal (amplitude) mode of the order parameter. These results suggest a transition from a transverse collinear antiferromagnet to an amplitude-modulated spin-density-wave phase in a very weak magnetic field, which is unexpected for a system of weakly coupled Heisenberg spin-12\frac{1}{2}21​ chains.