Journal of Experimental and Theoretical Physics Letters

New polarization effect and collective excitation in S = 1/2 quasi-one-dimensional antiferromagnetic quantum spin chain

S. V. Demishev, A. V. Semeno, Hitoshi Ohta, S. Okubo, I. E. Tarasenko, T. V. Ishchenko, Nikolay E. Sluchanko

Published Nov 1, 2006• 2 citations

Abstract

Anomalous polarization characteristics of magnetic resonance in CuGeO3 doped with 2% Co impurity are reported. For the Faraday geometry, this mode is damped for the microwave field B ω aligned along a certain crystallographic direction, showing that the character of magnetic oscillation differs from the standard spin precession. The observed resonance coexists with the ESR on Cu2+ chains; it is argued not to be caused by “impurity” EPR, as previously claimed, but to correspond to a previously unknown collective mode of magnetic oscillations in an S = 1/2 AF quantum spin chain.

DOI: 10.1134/s0021364006170048

Related papers

New polarization effect and collective excitation in S=1/2 quasi 1D antiferromagnetic quantum spin chain

S. V. Demishev, A. V. Semeno, Hitoshi Ohta +4 more

arXiv:cond-mat/0609022Sep 1, 20060 citations

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

T. A. Soldatov, A. I. Smirnov

Physical review. B./Physical review. BNov 17, 20251 citation

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

Physical review. B./Physical review. BJan 18, 201712 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

Journal of the Physical Society of JapanJul 28, 20235 citations

Impurities in the weakly coupled quantum spin chains Sr2CuO3 and SrCuO2

Koushik Karmakar, Rabindranath Bag, M. Skoulatos +2 more

arXiv:1706.01262Physical review. B./Physical review. BJun 28, 201711 citations

Impurity spin dynamics in 2D antiferromagnets and superconductors

Matthias Vojta C, Chiranjeeb Buragohain, Subir Sachdev A

Jan 1, 20000 citations

Journal of Experimental and Theoretical Physics Letters

New polarization effect and collective excitation in S = 1/2 quasi-one-dimensional antiferromagnetic quantum spin chain

S. V. Demishev, A. V. Semeno, Hitoshi Ohta, S. Okubo, I. E. Tarasenko, T. V. Ishchenko, Nikolay E. Sluchanko

Published Nov 1, 2006• 2 citations

Publisher

Abstract

DOI: 10.1134/s0021364006170048

Related papers

New polarization effect and collective excitation in S=1/2 quasi 1D antiferromagnetic quantum spin chain

S. V. Demishev, A. V. Semeno, Hitoshi Ohta +4 more

Anomalous polarization characteristics of magnetic resonance in CuGeO3 doped with 2% of Co impurity are reported. For the Faraday geometry this mode is damped for the microwave field Bw aligned along a certain crystallographic direction showing that the character of magnetic oscillation differs from the standard spin precession. The observed resonance coexists with the ESR on Cu2+ chains and argued not to be caused by "impurity" EPR, as previously claimed, but to correspond to a previously unknown collective mode of magnetic oscillations in S=1/2 AF quantum spin chain.Anomalous polarization characteristics of magnetic resonance in CuGeO3 doped with 2% of Co impurity are reported. For the Faraday geometry this mode is damped for the microwave field Bw aligned along a certain crystallographic direction showing that the character of magnetic oscillation differs from the standard spin precession. The observed resonance coexists with the ESR on Cu2+ chains and argued not to be caused by "impurity" EPR, as previously claimed, but to correspond to a previously unknown collective mode of magnetic oscillations in S=1/2 AF quantum spin chain.

arXiv:cond-mat/0609022Sep 1, 20060 citations

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

T. A. Soldatov, A. I. Smirnov

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.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.

Physical review. B./Physical review. BNov 17, 20251 citation

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.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. BJan 18, 201712 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.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 JapanJul 28, 20235 citations

Impurities in the weakly coupled quantum spin chains Sr2CuO3 and SrCuO2

Koushik Karmakar, Rabindranath Bag, M. Skoulatos +2 more

We study the effect of nonmagnetic ${\mathrm{Zn}}^{2+}$ (spin-0) and magnetic ${\mathrm{Ni}}^{2+}$ (spin-1) impurities on the ground state and low-lying excitations of the quasi-one-dimensional spin- $1/2$ Heisenberg antiferromagnet ${\mathrm{Sr}}_{2}{\mathrm{CuO}}_{3}$ using inelastic neutron scattering, specific heat, and bulk magnetization measurements. We show that 1% ${\mathrm{Ni}}^{2+}$ doping in ${\mathrm{Sr}}_{2}{\mathrm{CuO}}_{3}$ results in a sizable spin gap in the spinon excitations, analogous to the case of Ni doped ${\mathrm{SrCuO}}_{2}$ previously reported [Simutis et al., Phys. Rev. Lett. 111, 067204 (2013)]. However, a similar level of ${\mathrm{Zn}}^{2+}$ doping in ${\mathrm{SrCuO}}_{2}$ , investigated here for comparison, did not reveal any signs of a spin gap. Magnetic ordering temperature was found to be suppressed in the presence of both ${\mathrm{Zn}}^{2+}$ and ${\mathrm{Ni}}^{2+}$ impurities; however, the rate of suppression due to ${\mathrm{Ni}}^{2+}$ was found to be much more pronounced than for ${\mathrm{Zn}}^{2+}$ . Effect of magnetic field on the ordering temperature is investigated. We found that with increasing magnetic field, not only the magnetic ordering temperature gradually increases but the size of specific heat anomaly associated with the magnetic ordering also progressively enhances, which can be qualitatively understood as due to the field induced suppression of quantum fluctuations.We study the effect of nonmagnetic ${\mathrm{Zn}}^{2+}$ (spin-0) and magnetic ${\mathrm{Ni}}^{2+}$ (spin-1) impurities on the ground state and low-lying excitations of the quasi-one-dimensional spin-$1/2$ Heisenberg antiferromagnet ${\mathrm{Sr}}_{2}{\mathrm{CuO}}_{3}$ using inelastic neutron scattering, specific heat, and bulk magnetization measurements. We show that 1% ${\mathrm{Ni}}^{2+}$ doping in ${\mathrm{Sr}}_{2}{\mathrm{CuO}}_{3}$ results in a sizable spin gap in the spinon excitations, analogous to the case of Ni doped ${\mathrm{SrCuO}}_{2}$ previously reported [Simutis et al., Phys. Rev. Lett. 111, 067204 (2013)]. However, a similar level of ${\mathrm{Zn}}^{2+}$ doping in ${\mathrm{SrCuO}}_{2}$, investigated here for comparison, did not reveal any signs of a spin gap. Magnetic ordering temperature was found to be suppressed in the presence of both ${\mathrm{Zn}}^{2+}$ and ${\mathrm{Ni}}^{2+}$ impurities; however, the rate of suppression due to ${\mathrm{Ni}}^{2+}$ was found to be much more pronounced than for ${\mathrm{Zn}}^{2+}$. Effect of magnetic field on the ordering temperature is investigated. We found that with increasing magnetic field, not only the magnetic ordering temperature gradually increases but the size of specific heat anomaly associated with the magnetic ordering also progressively enhances, which can be qualitatively understood as due to the field induced suppression of quantum fluctuations.

arXiv:1706.01262Physical review. B./Physical review. BJun 28, 201711 citations

Impurity spin dynamics in 2D antiferromagnets and superconductors

Matthias Vojta C, Chiranjeeb Buragohain, Subir Sachdev A

We discuss the universal theory of localized impurities in the paramagnetic state of 2D antiferromagnets where the spin gap is assumed to be significantly smaller than a typical exchange energy. We study the impurity spin susceptibility near the host quantum transition from a gapped paramagnet to a Néel state, and we compute the impurity-induced damping of the spin-1 mode of the gapped antiferromagnet. Under suitable conditions our results apply also to d-wave superconductors. Doped antiferromagnets (AF) have been the subject of intense studies in the context of the cuprate high-temperature superconductors and other layered transition metal compounds. We present a quantum theory of a particular class of doped AF where it is possible to neglect the coupling between the spin and charge degrees of freedom and consider a theory of the spin excitations alone. Such a theory will apply to (i) quasi-2D ‘spin gap ’ insulators like SrCu2O3 or NaV2O5 inWe discuss the universal theory of localized impurities in the paramagnetic state of 2D antiferromagnets where the spin gap is assumed to be significantly smaller than a typical exchange energy. We study the impurity spin susceptibility near the host quantum transition from a gapped paramagnet to a Néel state, and we compute the impurity-induced damping of the spin-1 mode of the gapped antiferromagnet. Under suitable conditions our results apply also to d-wave superconductors. Doped antiferromagnets (AF) have been the subject of intense studies in the context of the cuprate high-temperature superconductors and other layered transition metal compounds. We present a quantum theory of a particular class of doped AF where it is possible to neglect the coupling between the spin and charge degrees of freedom and consider a theory of the spin excitations alone. Such a theory will apply to (i) quasi-2D ‘spin gap ’ insulators like SrCu2O3 or NaV2O5 in

Jan 1, 20000 citations

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.

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.

We study the effect of nonmagnetic

{\mathrm{Zn}}^{2+}

(spin-0) and magnetic

{\mathrm{Ni}}^{2+}

(spin-1) impurities on the ground state and low-lying excitations of the quasi-one-dimensional spin-

1/2

Heisenberg antiferromagnet

{\mathrm{Sr}}_{2}{\mathrm{CuO}}_{3}

using inelastic neutron scattering, specific heat, and bulk magnetization measurements. We show that 1%

{\mathrm{Ni}}^{2+}

doping in

{\mathrm{Sr}}_{2}{\mathrm{CuO}}_{3}

results in a sizable spin gap in the spinon excitations, analogous to the case of Ni doped

{\mathrm{SrCuO}}_{2}

previously reported [Simutis et al., Phys. Rev. Lett. 111, 067204 (2013)]. However, a similar level of

{\mathrm{Zn}}^{2+}

doping in

{\mathrm{SrCuO}}_{2}

, investigated here for comparison, did not reveal any signs of a spin gap. Magnetic ordering temperature was found to be suppressed in the presence of both

{\mathrm{Zn}}^{2+}

and

{\mathrm{Ni}}^{2+}

impurities; however, the rate of suppression due to

{\mathrm{Ni}}^{2+}

was found to be much more pronounced than for

{\mathrm{Zn}}^{2+}

. Effect of magnetic field on the ordering temperature is investigated. We found that with increasing magnetic field, not only the magnetic ordering temperature gradually increases but the size of specific heat anomaly associated with the magnetic ordering also progressively enhances, which can be qualitatively understood as due to the field induced suppression of quantum fluctuations.