Dynamical properties of a Haldane-gap antiferromagnet

Golinelli, O.; Jolicœur, Thierry; Lacaze, R.

doi:10.1088/0953-8984/5/9/024

Cited by 35 publications

(40 citation statements)

References 44 publications

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“…The excitation spectra of an isolated Haldane chain were investigated in great detail by several theoretical methods including quantum monte-carlo (QMC) [6], Exact diagonalization (ED) [7] and density matrix renormalization group (DMRG) [8] as well as experimental techniques [9,10]. The excitation spectra were well understood as gapped dispersive excitation of magnons (S = 1).…”

Section: Spin-1 Heisenberg Antiferromagnetic (Afm) Chains Ormentioning

confidence: 99%

Consequences of critical interchain couplings and anisotropy on a Haldane chain

et al. 2015

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Effects of interchain couplings and anisotropy on a Haldane chain have been investigated by single crystal inelastic neutron scattering and density functional theory (DFT) calculations on the model compound SrNi2V2O8. Significant effects on low energy excitation spectra are found where the Haldane gap (∆0 ≈ 0.41J; where J is the intrachain exchange interaction) is replaced by three energy minima at different antiferromagnetic zone centers due to the complex interchain couplings. Further, the triplet states are split into two branches by single-ion anisotropy. Quantitative information on the intrachain and interchain interactions as well as on the single-ion anisotropy are obtained from the analyses of the neutron scattering spectra by the random phase approximation (RPA) method. The presence of multiple competing interchain interactions is found from the analysis of the experimental spectra and is also confirmed by the DFT calculations. The interchain interactions are two orders of magnitude weaker than the nearest-neighbour intrachain interaction J = 8.7 meV. The DFT calculations reveal that the dominant intrachain nearest-neighbor interaction occurs via nontrivial extended superexchange pathways Ni-O-V-O-Ni involving the empty d orbital of V ions. The present single crystal study also allows us to correctly position SrNi2V2O8 in the theoretical D-J ⊥ phase diagram [T. Sakai and M. Takahashi, Phys. Rev. B 42, 4537 (1990)] showing where it lies within the spin-liquid phase.

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Section: Spin-1 Heisenberg Antiferromagnetic (Afm) Chains Ormentioning

confidence: 99%

Consequences of critical interchain couplings and anisotropy on a Haldane chain

et al. 2015

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“…17,18 Though clearly oversimplified, for a magnetic field applied parallel to any of the principal anisotropy axes this method is known to give the same values of H c as more sophisticated calculations based on the quantum non-linear sigma-model 14 or mapping to Mayorana fermions. 12 For a field in the (x, z) plane applied at an angle φ to the magnetic easy axis z, the perturbative result for H c is:…”

Section: 6mentioning

confidence: 99%

Half-ordered state in the anisotropic Haldane-gap antiferromagnetNi(C5D14N2)2
Zheludev
¹
,
Grenier
²
,
Ressouche
³

et al. 2005
Phys. Rev. B
12
1
13
0
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Neutron diffraction experiments performed on the Haldane gap material Ni(C5D14N2)2N3(PF6)in high magnetic fields applied at an angle to the principal anisotropy axes reveal two consecutive fieldinduced phase transitions. The low-field phase is the gapped Haldane state, while at high fields the system exhibits 3-dimensional long-range Néel order. In a peculiar phase found at intermediate fields only half of all the spin chains participate in the long-range ordering, while the other half remains disordered and gapped. PACS numbers:High-field phase transitions in quantum antiferromagnets (AFs) have recently drawn a great deal of attention. Of particular interest is field-induced spin freezing exhibited by many quantum spin liquids. The massive triplet of low-lying S = 1 gap excitations (magnons) in such systems is subject to Zeeman splitting by external magnetic fields. A soft-mode quantum phase transition occurs when the gap for one member of the triplet is driven to zero. The result is a Bose condensation of magnons. In the presence of magnetic anisotropy and weak inter-chain interactions, always found in real materials, the magnetized high-field phase is a Néel-like state with AF long-range order. The phase transition itself and the peculiarities of the high-field phase have been studied experimentally in several model materials including the Haldane-gap antiferromagnets1,2,3,4,5,6 and NDMAZ (Ni (C 5 9 and dimer systems such as TlCuCl 3 10 and Cs 3 Cr 2 Br 9 . 11It has been long established that magnetic anisotropy, which is particularly important for S = 1 materials, has a strong impact on the phase transition. The value of the critical field H c depends on the relative orientation of the applied field and the anisotropy tensor.12,13,14 A very interesting case is that of NDMAP. This compound features two equivalent sets of Haldane spin chains with non-collinear local anisotropy axes. To date, all experiments were performed in magnetic fields applied along the principal axes of the orthorhombic crystal structure that are also the macroscopic magnetic anisotropy axes. In these geometries all tilts of the local anisotropy axes relative to the field direction are the same for the two chain types. In the present study we investigate a less symmetric scenario, in which the magnetic field is applied in a general direction relative to the crystal axes. We find two consecutive field-induced transitions from the quantum-disordered spin liquid to ordered Néel phase, with a novel "half-ordered" phase in-between. • relative to the c axis. The tilt direction is opposite for type-A and type-B chains. The field H is applied at an angle ψ relative to the c axis of the crystal and forms unequal angles φA and φB with the anisotropy axes zA and zB, respectively.The crystal structure of NDMAP (orthorhombic space group P nmn, a = 18.046Å, b = 8.705Å, and c = 6.139Å) was described in detail in Ref.4 . The S = 1 chains run along the crystallographic c axis. The inchain exchange constant is J = 2.6 meV. Inter-chain interactions are mu...

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“…The fact that only the neutral gap vanishes at the HI-CDW transition is a signature that the string order O z along the z-axis remains finite, where O It is well-known that in the Haldane phase, the neutral gap changes from one type to the other [6,23,35] and is emphasized in Fig. 1, where around V C ≈ 0.75U , the neutral and the charge gaps start having different values.…”

Section: Mott-haldane-cdw Transitionsmentioning

confidence: 97%

“…Even though the phase diagram of the extended BHM is now well understood, the excitation spectra of the various ground states have been less studied [23,24], essentially because the numerical methods providing the ground state properties, such as exact diagonalization or QMC, become limited in the dynamical domain. More recently, for quasi-1D systems, the extension of the density matrix renormalization group method (DMRG) to the time domain or, equivalently, the time evolving density matrix method (TEBD) have proved to be extremely successful in probing the dynamical properties of the system, thereby providing reliable excitation spectrum [25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Excitation and dynamics in the extended Bose-Hubbard model

Grémaud

Batrouni

2016

Phys. Rev. B

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The one-dimensional extended bosonic Hubbard model has been shown to exhibit a variety of phases ranging from Mott insulator and superfluid to exotic supersolids and Haldane insulators depending on the filling and the relative value of the contact (U ) and near neighbor (V ) interaction strengths. In this paper we use the density matrix renormalization group and the time evolving block decimation numerical methods to study in detail the dynamics and excitation spectra of this model in its various phases. In particular, we study in detail the behavior of the charge and neutral gaps which characterize the Mott, charge density and Haldane insulating phases. We also show that in addition to the gapless modes at k = 0, the supersolid phase exhibits gapless modes at a finite k which depends on the filling.

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Dynamical properties of a Haldane-gap antiferromagnet

Cited by 35 publications

References 44 publications

Consequences of critical interchain couplings and anisotropy on a Haldane chain

Consequences of critical interchain couplings and anisotropy on a Haldane chain

Half-ordered state in the anisotropic Haldane-gap antiferromagnetNi(C5D14N2)2
Zheludev
¹
,
Grenier
²
,
Ressouche
³

et al. 2005
Phys. Rev. B
12
1
13
0
View full text Add to dashboard Cite

Excitation and dynamics in the extended Bose-Hubbard model

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Dynamical properties of a Haldane-gap antiferromagnet

Cited by 35 publications

References 44 publications

Consequences of critical interchain couplings and anisotropy on a Haldane chain

Consequences of critical interchain couplings and anisotropy on a Haldane chain

Half-ordered state in the anisotropic Haldane-gap antiferromagnetNi(C5D14N2)2Zheludev1, Grenier2, Ressouche3 et al. 2005Phys. Rev. B121130View full textAdd to dashboardCite

Excitation and dynamics in the extended Bose-Hubbard model

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Half-ordered state in the anisotropic Haldane-gap antiferromagnetNi(C5D14N2)2
Zheludev
¹
,
Grenier
²
,
Ressouche
³

et al. 2005
Phys. Rev. B
12
1
13
0
View full text Add to dashboard Cite