Field-Induced Gap Formation in Yb 4As 3

Oshikawa, Masaki; Ueda, Kazuo; Aoki, Hidekazu; Ochiai, Akira; Kohgi, M.

doi:10.1143/jpsj.68.3181

Cited by 93 publications

(92 citation statements)

References 16 publications

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“…Recently, microscopic analysis [1] on Yb 4 As 3 , a typical system showing field induced gap opening at low temperature, confirmed that its effective Hamiltonian is a S=1/2 Heisenberg model with Dzyaloshinsky-Moriya (DM) interaction. This microscopic analysis supports previous scenario for the field induced gap opening due to the DM interaction [2,3,4], and stimulates more precise and detailed comparison between experiment and theory.…”

Section: Introductionsupporting

confidence: 89%

Thermodynamic Properties of theS=1/2 Heisenberg Chain with Staggered Dzyaloshinsky–Moriya Interaction

Shibata

Ueda

2001

J. Phys. Soc. Jpn.

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Thermodynamic properties of the S=1/2 Heisenberg chain in transverse staggered magnetic field H y s and uniform magnetic field H x perpendicular to the staggered field is studied by the finitetemperature density-matrix renormalization-group method. The uniform and staggered magnetization and specific heat are calculated from zero temperature to high temperatures up to T /J = 4 under various strength of magnetic fields from H y s /J, H x /J = 0 to 2.4. The specific heat and magnetization of the effective Hamiltonian of the Yb4As3 are also presented, and field induced gap formation and diverging magnetic susceptibility at low temperature are shown.

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Section: Introductionsupporting

confidence: 89%

Thermodynamic Properties of theS=1/2 Heisenberg Chain with Staggered Dzyaloshinsky–Moriya Interaction

Shibata

Ueda

2001

J. Phys. Soc. Jpn.

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“…Recently some novel magnetic properties were discovered in a variety of quasi-one dimensional materials, such as copper benzoate Cu(C 6 D 5 COO) 2 3D 2 O[1, 2], Yb 4 As 3 [3,4,5] and BaCu 2 Si 2 O 7 [6]. In these materials, the Dzyaloshinskii-Moriya (DM) interaction [7,8,9] plays an important role, especially in an applied magnetic field.…”

mentioning

confidence: 99%

Effects of the Dzyaloshinskii-Moriya Interaction on Low-Energy Magnetic Excitations in Copper Benzoate

et al. 2003

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We have investigated the physical effects of the Dzyaloshinskii-Moriya (DM) interaction in copper benzoate. In the low field limit, the spin gap is found to vary as H 2/3 ln 1/6 (J/µBHs) (Hs: an effective staggered field induced by the external field H) in agreement with the prediction of conformal field theory, while the staggered magnetization varies as H 1/3 and the ln 1/3 (J/µBHs) correction predicted by conformal field theory is not confirmed. The linear scaling behavior between the momentum shift and the magnetization is broken. We have determined the coupling constant of the DM interaction and have given a complete quantitative account for the field dependence of the spin gaps along all three principal axes, without resorting to additional interactions like interchain coupling. A crossover to strong applied field behavior is predicted for further experimental verification. . In these materials, the Dzyaloshinskii-Moriya (DM) interaction [7,8,9] plays an important role, especially in an applied magnetic field. This has stimulated extensive investigation on the physical properties of the DM interaction. However, this interaction is rather difficult to handle analytically, which has brought much uncertainty in the interpretation of experimental data and has limited our understanding of many interesting quantum phenomena of low-dimensional magnetic materials.For copper benzoate, Dender et al [1,2] found that the spin excitation gap shows a peculiar field dependence, ∆ ∼ H 0.65 , in low fields. On the contrary, excitations remain gapless in the S=1/2 Heisenberg model below a critical field. Oshikawa and Affleck (OA) suggested that this field dependence of the gap is due to a staggered magnetic field induced by the DM interaction in addition to the staggered g-factor in a uniform field [9,10]. However, a satisfactory explanation for the field-dependence of the energy gaps in all three directions is still lacking [11,12]. It was argued that the inconsistency between the experimental data and theoretical results might be due to the neglect of the interchain coupling and/or anisotropic interaction terms in the low-field effective model used by Oshikawa and Affleck [9,11]. We believe this issue can be clarified by a thorough study of the DM interaction and a direct comparison with experiments.Copper benzoate is a quasi-1D spin-1/2 antiferromagnetic Heisenberg system. The chain direction is the caxis. It contains two types of alternating and slightly tilted CuO 8 octahedra. This leads to two inequivalent Cu ++ ions and an alternating DM coupling [13]. In an applied field, copper benzoate can be modeled by the following Hamiltonian,( 1) where the three terms in the summation are the antiferromagnetic Heisenberg, DM and Zeeman splitting interactions, respectively. The exchange coupling constant J, determined from the neutron scattering measurements, is about 1.57meV. The DM interaction is much weaker than the Heisenberg term. The D-vector, primarily aligned along the a ′′ axis, will be determined numerically. g u and ...

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“…A finite mass, or excitation gap, may be introduced by various deviations from the AF Heisenberg model like xxz-exchange anisotropy, dimerization by lattice distortion or staggered flelds induced by Dzyaloshinskii-Moriya interaction or alternating g tensors. While the former and the latter of these mechanisms were suggested as being important for the C(T, B) behavior in Cu benzoate [15], the staggered field was, as pointed out before, held responsible for the gap-opening effect in Yb 4 Αs3 [13]. We still think that the existence of solitons in Yb 4 Αs3 could possibly be due to the xxz anisotropy as considered in our classical approach.…”

Section: Resultsmentioning

confidence: 48%

“…On the other hand, the 1D AF Heisenberg model cannot explain the strong field dependence of the low-temperature specific heat [5][6][7]. Interchain coupling [12] and, alternatively, small corrections to the Heisenberg exchange [13] or intrachain dipolar interactions [13] have been proposed as possible reasons of this behavior. Our results for the specific heat, thermal expansion, and thermal conductivity clearly indicate that in the quantum-spin chains of charge-ordered Yb4 Αs3 , excitations of selitonic nature are present which lead to peaks in the spin contributions to C (T) and especially to α(T) as well as to minima in KB (Τ)/κ 0 (Τ) An anomaly at B = 3.5 Τ is clearly visible also in the C(T)/T data for Cu benzoate [1], strikingly similar to the soliton peak in the specific-heat data of Fig.…”

Section: Resultsmentioning

confidence: 99%

“…If in the case of Yb 4 Αs3 one takes into account the presence of the As atoms, one finds that (i) the g tensor is alternating along the (111) direction and (ii) an inversion-symmetry center between two adjacent Yb3+ ions is lacking, prerequisite fοr the Dzyaloshinskii-Moriya interaction to operate. The staggered-field mechanism may, thus, also be relevant and explain the field-induced gap in Yb 4 Αs3 as proposed in [13], employing the quantum SG model [14,15]. The latter, however, has the disadvantage of being a low-energy and low-temperature model.…”

Section: Specific Heatmentioning

confidence: 97%

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Magnon and Soliton Excitations in the Carrier-Poor, One-Dimensional S=1/2 Antiferromagnet Yb₄As₃

et al. 2000

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Field-Induced Gap Formation in Yb₄As₃

Cited by 93 publications

References 16 publications

Thermodynamic Properties of theS=1/2 Heisenberg Chain with Staggered Dzyaloshinsky–Moriya Interaction

Thermodynamic Properties of theS=1/2 Heisenberg Chain with Staggered Dzyaloshinsky–Moriya Interaction

Effects of the Dzyaloshinskii-Moriya Interaction on Low-Energy Magnetic Excitations in Copper Benzoate

Magnon and Soliton Excitations in the Carrier-Poor, One-Dimensional S=1/2 Antiferromagnet Yb₄As₃

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Field-Induced Gap Formation in Yb 4As 3

Cited by 93 publications

References 16 publications

Thermodynamic Properties of theS=1/2 Heisenberg Chain with Staggered Dzyaloshinsky–Moriya Interaction

Thermodynamic Properties of theS=1/2 Heisenberg Chain with Staggered Dzyaloshinsky–Moriya Interaction

Effects of the Dzyaloshinskii-Moriya Interaction on Low-Energy Magnetic Excitations in Copper Benzoate

Magnon and Soliton Excitations in the Carrier-Poor, One-Dimensional S=1/2 Antiferromagnet Yb4As3

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Field-Induced Gap Formation in Yb₄As₃

Magnon and Soliton Excitations in the Carrier-Poor, One-Dimensional S=1/2 Antiferromagnet Yb₄As₃