Disorder and Quantum Spin Ice

Martín, Nicolás Bas; Bonville, P.; Lhotel, Elsa; Guitteny, S.; Wildes, A.; Decorse, Claudia; Hatnean, Monica Ciomaga; Balakrishnan, G.; Mirebeau, I.; Petit, S.

doi:10.1103/physrevx.7.041028

Cited by 49 publications

(65 citation statements)

References 49 publications

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“…This does not necessitate that frustration is magnetically driven; rather our results suggest that the frustration is structurally driven with significant impacts on the magnetic ordering, enhancing spin-liquid behavior and at the very least creating spin-glass behavior. Such effects have recently been observed 43, 44 , and are important for understanding the underlying physics of the spin-ice state. More thoroughly, a β-cristobalite distortion may not significantly alter bond distances, but bond angles, such as A –O– A , change drastically, and next-nearest neighbor distances are altered even more dramatically.…”

Section: Discussionmentioning

confidence: 87%

Universal geometric frustration in pyrochlores

et al. 2018

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Materials with the pyrochlore/fluorite structure have diverse technological applications, from magnetism to nuclear waste disposal. Here we report the observation of structural instability present in the pyrochlores A2Zr2O6Oʹ (A = Pr, La) and Yb2Ti2O6Oʹ, that exists despite ideal stoichiometry, ideal cation-ordering, the absence of lone pair effects, and a lack of magnetic order. Though these materials appear to have good long-range order, local structure probes find displacements, of the order of 0.01 nm, within the pyrochlore framework. The pattern of displacements of the A2Oʹ sublattice mimics the entropically-driven fluxional motions characteristic of and well-known in the silica mineral β-cristobalite. The universality of such displacements within the pyrochlore structure adds to the known structural diversity and explains the extreme sensitivity to composition found in quantum spin ices and the lack of ferroelectric behavior in pyrochlores.

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Section: Discussionmentioning

confidence: 87%

Universal geometric frustration in pyrochlores

et al. 2018

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“…The gauge theory description of a spin liquid can take a number of different forms, ranging from intricate stringnet models [9] to familiar U (1) Maxwell theory. The latter case has a number of promising experimental candidates in the form of the "spin ice" pyrochlore materials, including the classical spin ices Dy 2 Ti 2 O 7 and Ho 2 Ti 2 O 7 , as well as the quantum spin ices Yb 2 Ti 2 O 7 and Pr 2 Zr 2 O 7 [7,[10][11][12][13][14][15][16]. Over a range of low temperatures, these materials exist in a symmetry-preserving phase consistent with the expected behavior of a deconfined Coulomb phase of an emergent U (1) gauge field.…”

Section: Introductionmentioning

confidence: 99%

Pinch point singularities of tensor spin liquids

et al. 2018

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Recently, a new class of three-dimensional spin liquid models have been theoretically discovered, which feature generalized Coulomb phases of emergent symmetric tensor U (1) gauge theories. These "higher rank" tensor models are particularly intriguing due to the presence of quasi-particles with restricted mobility, such as fractons. We investigate universal experimental signatures of tensor Coulomb phases. Most notably, we show that tensor Coulomb spin liquids (both quantum and classical) feature characteristic pinch-point singularities in their spin-spin correlation functions, accessible via neutron scattering, which can be readily distinguished from pinch points in conventional U (1) spin liquids. These pinch points can thus serve as a crisp experimental diagnostic for such phases. We also tabulate the low-temperature heat capacity of various tensor Coulomb phases, which serves as a useful additional diagnostic in certain cases. arXiv:1806.04148v1 [cond-mat.str-el]

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“…(a) |Q|-dependence of the background subtracted first moment E as measured on MARI at T=5 K with an Ei=15 meV integrated over E=[2,8] meV. A fit to the first moment sum rule (Eq.…”

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confidence: 99%

“…Distances |dij| with corresponding non-negligible refined values of −nijJij ĵ i ·ĵj and nijJij from the fit of the first moment E (|Q|) (E=[2,8] meV) at 5 K to the first moment sum rule145 . The corresponding calculated spinorbit corrected Curie-Weiss constant θCW (Eq.…”

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confidence: 99%

Ordered magnetism in the intrinsically decorated jeff=12α−CoV3O8

et al. 2018

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The antiferromagnetic mixed valence ternary oxide α-CoV3O8 displays disorder on the Co 2+ site that is inherent to the Ibam space group resulting in a local selection rule requiring one Co 2+ and one V 4+ reside next to each other, thus giving rise to an intrinsically disordered magnet without the need for any external influences such as chemical dopants or porous media. The zero field structural and dynamic properties of α-CoV3O8 have been investigated using a combination of neutron and x-ray diffraction, DC susceptibility, and neutron spectroscopy. The low temperature magnetic and structural properties are consistent with a random macroscopic distribution of Co 2+ over the 16k metal sites. However, by applying the sum rules of neutron scattering we observe the collective magnetic excitations are parameterized with an ordered Co 2+ arrangement and critical scattering consistent with a three dimensional Ising universality class. The low energy spectrum is well-described by Co 2+ cations coupled via a three dimensional network composed of competing ferromagnetic and stronger antiferromagnetic superexchange within the ab plane and along c, respectively. While the extrapolated Weiss temperature is near zero, the 3D dimensionality results in long range antiferromagnetic order at T N ∼ 19 K. A crystal field analysis finds two bands of excitations separated in energy at ω ∼ 5 meV and 25 meV, consistent with a j eff = 1 2 ground state with little mixing between spin-orbit split Kramers doublets. A comparison of our results to the random 3D Ising magnets and other compounds where spin-orbit coupling is present indicate that the presence of an orbital degree of freedom, in combination with strong crystal field effects and well-separated j eff manifolds may play a key role in making the dynamics largely insensitive to disorder.

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Disorder and Quantum Spin Ice

Abstract: International audienc

Cited by 49 publications

References 49 publications

Universal geometric frustration in pyrochlores

Universal geometric frustration in pyrochlores

Pinch point singularities of tensor spin liquids

Ordered magnetism in the intrinsically decorated jeff=12α−CoV3O8

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