Quantum and thermal ionic motion, oxygen isotope effect, and superexchange distribution in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>La</mml:mtext><mml:mn>2</mml:mn></mml:msub></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mtext>CuO</mml:mtext><mml:mn>4</mml:mn></mml:msub></mml:math>

Häfliger, P. S.; Gerber, Simon; Pramod, R.; Schnells, Vera; Piazza, B. Dalla; Chati, Ralph; Pomjakushin, Vladimir; Conder, K.; Pomjakushina, E.; Dréau, Loïc Le; Christensen, Niels Bech; Syljuåsen, Olav F.; Normand, Bernard; Rønnow, Henrik M.

doi:10.1103/physrevb.89.085113

Cited by 17 publications

(23 citation statements)

References 57 publications

(119 reference statements)

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“…Regarding cuprates, one can estimate α ≈ 0.01. The superexchange parameter has a larger uncertainty, with indirect studies giving a range of γ = 3−14 [43,45] and a consideration of a wider class of materials suggesting an upper limit of γ ≤ 20 [31]. Thus, the microscopic upper bound on the spin-phonon coupling constant in 1D cuprates can be put at g max sp ≈ 0.2, justifying the weak-coupling treatment of the spin-boson scattering on phonons in Eq.…”

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confidence: 94%

Heat Transport in Spin Chains with Weak Spin-Phonon Coupling

Chernyshev

Rozhkov

2016

Phys. Rev. Lett.

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The heat transport in a system of S = 1/2 large-J Heisenberg spin chains, describing closely Sr2CuO3 and SrCuO2 cuprates, is studied theoretically at T J by considering interactions of the bosonized spin excitations with optical phonons and defects. Treating rigorously the multiboson processes, we derive a microscopic spin-phonon scattering rate that adheres to an intuitive picture of phonons acting as thermally populated defects for the fast spin excitations. The meanfree path of the latter exhibits a distinctive T -dependence reflecting a critical nature of spin chains and gives a close description of experiments. By the naturalness criterion of realistically small spinphonon interaction, our approach stands out from previous considerations that require large coupling constants to explain the data and thus imply a spin-Peierls transition, absent in real materials.PACS numbers: 75.10. Jm, 75.50.Ee, 75.40.Gb, 72.20.Pa The one-dimensional (1D) spin chains are among the first strongly-interacting quantum many-body systems ever studied [1, 2] and they remain a fertile ground for new ideas [3] and for developments of advanced theoretical and numerical [4, 5] methods. A number of physical realizations of spin-chain materials [6-10] have allowed for an unprecedentedly comprehensive comparisons between theory, numerical approaches, and experimental data [11][12][13]. Current theoretical challenges for these systems include their dynamical, non-equilibrium, and transport properties [14][15][16][17][18][19][20]. The transport phenomena are particularly challenging as the couplings to phonons and impurities, perturbations that are extrinsic to the often integrable spin systems, become crucial [21][22][23][24][25][26].In this Letter, we address the problem of heat transport in 1D spin-chain systems by considering coupling of spins to optical phonons and impurities and having in mind a systematic experimental thermal conductivity study in the high-quality, single-crystalline, large-J spin-chain cuprates Sr 2 CuO 3 and SrCuO 2 that has been recently conducted [27][28][29][30]. Several attempts to develop a suitable formalism to describe this phenomenon have been made in the past [24][25][26]. However, these approaches either relied on unrealistic choices of parameters [24,26] or offered only qualitative insights [24,25].Below we attempt to bridge the gap between experiment and theory. We argue that the heat conductivity by spin excitations can be quantitatively described within the bosonization framework with the large-momentum scattering by optical phonons or impurities. For weak impurities, scattering grows stronger at lower temperature, a feature intimately related to a critical character of the S = 1/2 Heisenberg chains [26]. Taking into account multi-spin-boson processes, it follows naturally from our microscopic calculations that scattering by phonons bears a close similarity to that by weak impurities, except that the phonons are thermally populated and thus control heat transport at high T . This is also in acco...

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confidence: 94%

Heat Transport in Spin Chains with Weak Spin-Phonon Coupling

Chernyshev

Rozhkov

2016

Phys. Rev. Lett.

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“…Even large thermal displacement ellipsoids indicate structural features that require a careful evaluation. Bond lengths should be corrected for "thermal" displacement because not less than their inverse fifth power is used in calculations (see for instance [51]). …”

Section: Resultsmentioning

confidence: 99%

Crystal Growth of Cu6(Ge,Si)6O18&#183;6H2O and Assignment of UV-VIS Spectra in Comparison to Dehydrated Dioptase and Selected Cu(II) Oxo-Compounds Including Cuprates

Otto¹

2017

WJCMP

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Low-dimensional quantum spin systems with the Cu 2+ central ion are still in the focus of experimental and theoretical research. Here is reported on growth of mm-sized single-crystals of the low-dimensional S = 1/2 spin compound Cu 6 (Ge,Si) 6 O 18 ·6H 2 O by a diffusion technique in aqueous solution. A route to form Si-rich crystals down to possible dioptase, the pure silicate, is discussed.Motivated by previously reported incorrect assignments of UV-VIS spectra, the assignment of dd excitations from such spectra of the hexahydrate and the fully dehydrated compound is proposed in comparison to dioptase and selected Cu(II) oxo-compounds using bond strength considerations. Non-doped cuprates as layer compounds show higher excitation energies than the title compound. However, when the antiferromagnetic interaction energy as J z ·ln (2)

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“…While scattering of magnons among themselves and due to fluctuations of the order-parameter in the paramagnetic state has received significant attention in the past, 12 the impact of phonons on magnon lifetime and other properties of magnetic excitations has only recently begun receiving attention. 13 In this context, the current work focuses on the physics of magnon scattering and its role in magnetic thermal transport of quantum antiferromagnets. While our approaches are generic, our analysis is strongly motivated by La 2 CuO 4 and related cuprates.…”

Section: 10mentioning

confidence: 99%

“…16 as an ultimate result of the thermal expansion. With the large value of J and an apparent insignificant impact of the expansion on the average value of J in the 0 − 300K range 13 in La 2 CuO 4 , it is hard to estimate at what T such dramatic effects can be expected to onset.…”

Section: 28mentioning

confidence: 99%

Thermal conductivity inlarge−Jtwo-dimensional antiferromagnets: Role of phonon scattering

Chernyshev

Brenig

2015

Phys. Rev. B

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Motivated by the recent heat transport experiments in 2D antiferromagnets, such as La2CuO4, where the exchange coupling J is larger than the Debye energy ΘD, we discuss different types of relaxation processes for magnon heat current with a particular focus on coupling to 3D phonons. We study thermal conductivity by these in-plane magnetic excitations using two distinct techniques, Boltzmann formalism within the relaxation-time approximation and memory-function approach. Within these approaches, a close consideration is given to the scattering of magnons by both acoustic and optical branches of phonons. A remarkable accord between the two methods with regards to the asymptotic behavior of the effective relaxation rates is demonstrated. Additional scattering mechanisms, due to grain boundaries, impurities, and finite correlation length in the paramagnetic phase, are discussed and included in the calculations of the thermal conductivity κ(T ). Again, we demonstrate a close similarity of the results from the two techniques of calculating κ(T ). Our complementary approach strongly suggests that scattering from optical or zone-boundary phonons is important for magnon heat current relaxation in a high temperature window of ΘD T J.

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Quantum and thermal ionic motion, oxygen isotope effect, and superexchange distribution inLa2CuO4

Cited by 17 publications

References 57 publications

Heat Transport in Spin Chains with Weak Spin-Phonon Coupling

Heat Transport in Spin Chains with Weak Spin-Phonon Coupling

Crystal Growth of Cu6(Ge,Si)6O18&#183;6H2O and Assignment of UV-VIS Spectra in Comparison to Dehydrated Dioptase and Selected Cu(II) Oxo-Compounds Including Cuprates

Thermal conductivity inlarge−Jtwo-dimensional antiferromagnets: Role of phonon scattering

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Quantum and thermal ionic motion, oxygen isotope effect, and superexchange distribution inLa2CuO4

Cited by 17 publications

References 57 publications

Heat Transport in Spin Chains with Weak Spin-Phonon Coupling

Heat Transport in Spin Chains with Weak Spin-Phonon Coupling

Crystal Growth of Cu6(Ge,Si)6O18&amp;#183;6H2O and Assignment of UV-VIS Spectra in Comparison to Dehydrated Dioptase and Selected Cu(II) Oxo-Compounds Including Cuprates

Thermal conductivity inlarge−Jtwo-dimensional antiferromagnets: Role of phonon scattering

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Crystal Growth of Cu6(Ge,Si)6O18·6H2O and Assignment of UV-VIS Spectra in Comparison to Dehydrated Dioptase and Selected Cu(II) Oxo-Compounds Including Cuprates