Low temperature magnetization of the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi>S</mml:mi><mml:mo>=</mml:mo><mml:mstyle scriptlevel="1"><mml:mfrac bevelled="false"><mml:mn>1</mml:mn><mml:mn>2</mml:mn></mml:mfrac></mml:mstyle></mml:mrow></mml:math>kagome antiferromagnet<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi mathvariant="normal">Zn</mml:mi><mml:msub><mml:mi mathvariant="normal">Cu</mml:mi><mml:mn>3</mml:mn></

Bert, F.; Nakamae, Sawako; Ladieu, F.; L’Hôte, D.; Bonville, P.; Duc, F.; Trombe, Jean‐Christian; Mendels, P.

doi:10.1103/physrevb.76.132411

Cited by 133 publications

(145 citation statements)

References 21 publications

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“…Because the spin flip dynamics is enhanced, we expect the saturation shifts down as the field increases. In the very recent manuscript [11], this effect is observed in the powder sample. The applied magnetic field has two components: one is parallel to the hard plane and the other is longitudinal to the easy axis.…”

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confidence: 96%

Thermodynamics of the quantum Ising model in the two-dimensional kagome lattice

Chern

Tsukamoto

2008

Phys. Rev. B

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In the classical Ising model on the kagome lattice, there are macroscopically degenerate classical states with exponentially-decayed spin correlation. As the singular quantum perturbation is introduced by applying the transverse magnetic field, the quantum ground state remains disordered, dubbed by "disorder-by-disorder". Here we compute the temperature dependence of the spin susceptibility and the specific heat for difference strength of the field to understand the effect of the singular quantum perturbation in this system. The relevance to the ZnCu3(OH)6Cl2 will be also commented.PACS numbers: 75.30. Gw, 75.40.Cx, 75.40.Mg Macroscopically degenerate states often occur in the classical level in the anti-ferromagnetic systems that the exchange energy can not be perfectly shared by all the nearest neighbor spins. It happens naturally if spins are placed in the triangular geometry in the two-dimensional lattices. In two dimensions, triangles can share the edges to form the triangular network or share the corners to form the kagome lattice. If we consider the classical Ising dynamics in these two systems, both of them show macroscopically degenerate classical ground states. However, the spin correlation in these two systems are very different, which determines the fate of the consequent quantum ground states when the quantum dynamics is introduced. When the transverse magnetic field is introduced by the following Hamiltonian,where S k = σ k /2 and σ k are the Pauli spin matrices and J is taken to be positive, the quantum ground state in the triangular lattice favors an spin-ordered ground state, the maximally-flippable state, because the spin correlation is critical in the classical model. On the other hand, the quantum ground state in the kagome case remains disordered because the spin correlation is exponentiallydecayed [1,2]. In this paper, we focus on the kagome case and compute its thermodynamic properties with various Γ. At Γ = 0, the spin susceptibility shows dramatic upturn in the low temperature and diverges at the zero temperature. For non-zero Γ, we also see the significant upturn but it saturates at the zero temperature. Our calculation is the first results on the thermodynamic quantities to distinguish the classical disordered state and the quantum disorder states. Furthermore, as the macroscopically degenerate classical states lead to the residual entropy at T = 0, the quantum dynamics which lifts the degeneracy results in additional peak in the specific heat in the low temperature at the order of Γ. Due to these properties, our model might be relevant to the recent discovered ZnCu 3 (OH) 6 Cl 2 , which shows the abnormal upturn in the spin susceptibility and saturates at T = 0. There have been several theoretical papers trying to describe this unusual property. A straightforward interpretation is the presence of the impurity[3] that contributes additionally to the susceptibility. However, a naive inclusion of the contribution from the impurity can explain the data only above 20K [4]. Different ang...

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confidence: 96%

Thermodynamics of the quantum Ising model in the two-dimensional kagome lattice

Chern

Tsukamoto

2008

Phys. Rev. B

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“…32 A number of experimental probes point to the occupation of between 14% and 23% of the interplane Zn sites by Cu 2+ ions, depending on the synthesis method and experimental probe. [24][25][26]33,34 The resulting "antisite" spins arising from Cu 2+ ions located on the interplane Zn sites couple only weakly to the spins on the kagome layers (see Fig. 2).…”

Section: Introductionmentioning

confidence: 99%

“…[24][25][26] Furthermore, neutron spectroscopy data, measured at temperatures down to 50 mK and energies down to 0.1 meV, point to a continuum of magnetic excitations. 23,27,28 Hence, the spins do not disappear as T → 0 nor do they freeze into a static arrangement.…”

Section: Introductionmentioning

confidence: 99%

Extension of the zinc paratacamite phase diagram: Probing the effect of spin vacancies in anS=12kagome antiferromagnet

et al. 2012

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“…After years of experimental searches, several promising candidates finally emerged, including the "perfect" spin-1 2 kagome lattice herbertsmithite ZnCu 3 ͑OH͒ 6 Cl 2 , which shows no signs of magnetic ordering down to a temperature of 50 mK, despite having a nearestneighbor antiferromagnetic exchange J Ϸ 190 K. [1][2][3] Ever since the successful synthesis of herbertsmithite, 4 a host of experimental techniques have been applied to study the material, including thermodynamic measurements, 1,3,5,6 neutron diffraction, 1,7 NMR, 3,8,9 and SR. 2,3 Unfortunately, the experimental results accumulated thus far are still insufficient to determine if the material is truly a quantum spin liquid. In particular, the valence-bond solid ͑VBS͒ state proposed in Refs.…”

Section: Introductionmentioning

confidence: 99%

Raman signature of the U(1) Dirac spin-liquid state in the spin-12kagome system

Liu

et al. 2010

Phys. Rev. B

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We followed the Shastry-Shraiman formulation of Raman scattering in Hubbard systems and considered the Raman intensity profile in the spin-1 2 "perfect" kagome lattice herbertsmithite ZnCu 3 ͑OH͒ 6 Cl 2 , assuming the ground state is well-described by the U͑1͒ Dirac spin-liquid state. In the derivation of the Raman T matrix, we found that the spin-chirality term appears in the A 2g channel in the kagome lattice at the t 4 / ͑ i − U͒ 3 order, but ͑contrary to the claims by Shastry and Shraiman͒ vanishes in the square lattice to that order. In the ensuing calculations on the spin-1 2 kagome lattice, we found that the Raman intensity profile in the E g channel is invariant under an arbitrary rotation in the kagome plane, and that in all ͑A 1g , E g , and A 2g ͒ symmetry channels the Raman intensity profile contains broad continua that display power-law behaviors at low energy, with exponent approximately equal to 1 in the A 2g channel and exponent approximately equal to 3 in the E g and the A 1g channels. For the A 2g channel, the Raman profile also contains a characteristic 1 / singularity, which arose in our model from an excitation of the emergent U͑1͒ gauge field.

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Low temperature magnetization of theS=12kagome antiferromagnetZnCu3

Cited by 133 publications

References 21 publications

Thermodynamics of the quantum Ising model in the two-dimensional kagome lattice

Thermodynamics of the quantum Ising model in the two-dimensional kagome lattice

Extension of the zinc paratacamite phase diagram: Probing the effect of spin vacancies in anS=12kagome antiferromagnet

Raman signature of the U(1) Dirac spin-liquid state in the spin-12kagome system

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