Monopole ordered phases in dipolar and nearest-neighbors Ising pyrochlore: From spin ice to the all-in–all-out antiferromagnet

Guruciaga, Pamela C.; Grigera, S. A.; Borzi, R. A.

doi:10.1103/physrevb.90.184423

Cited by 26 publications

(51 citation statements)

References 31 publications

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“…These values correspond to the plateaux observed in Fig. 12 With the peculiar exceptions of models where double charges were explicitly forbidden 37,38 , and 2D artificial kagome ice systems [40][41][42][43][44] , the FCSL has been noticeably elusive at equilibrium in 3D spin-ice models 46 , despite its deceptive simplicity.…”

Section: Numerical Setup For Field Quenchessupporting

confidence: 74%

“…The FCSL has been predicted theoretically 40,41 and observed experimentally [42][43][44] in nano-lithographic artificial kagome ice whose geometry prevents the existence of a charge-free Coulomb phase 45 . But in three dimensions, it has so far only been partially stabilized at equilibrium in the spin-ice model with dipolar interactions 46 , or requires four-body interactions 39 or the suppression of double charges 37,38 . The nonequilibrium magnetic-field quench proposed here provides a promising tool to realize this state and demonstrates the possibility of engineering a macroscopic state via nonequilibrium techniques 47 .…”

Section: Model and Summary Of Main Resultsmentioning

confidence: 99%

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Out-of-equilibrium dynamics and extended textures of topological defects in spin ice

et al. 2016

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We study the interplay of topological bottlenecks and energetic barriers to equilibration in a Coulomb spin liquid where a short-range energetic coupling between defects charged under an emergent gauge field supplements their entropic long-range Coulomb interaction. This work is motivated by the prevalence of memory effects observed across a wide range of geometrically frustrated magnetic materials, possibly including the spontaneous Hall effect observed in Pr2Ir2O7. Our model is canonical spin-ice model on the pyrochlore lattice, where farther-neighbour spin couplings give rise to a nearest-neighbor interaction between topological defects which can easily be chosen to be "unnatural" or not, i.e. attractive or repulsive between defects of equal gauge charge. Among the novel features of this model are the following. After applying a field quench, a rich dynamical approach to equilibrium emerges, dominated by multi-scale energy barriers responsible for long-lived magnetization plateaux. These even allow for the metastability of a "fragmented" spin liquid, an elusive regime where partial order co-exists with a spin liquid. Perhaps most strikingly, the attraction produces clusters of defects whose stability is due to a combination of energetic barriers for their break-up and proximity of opposite charges along with an entropic barrier generated by the topological requirement of annihilating a defect only together with an oppositely charged counterpart. These clusters may take the form of a "jellyfish" spin texture, comprising an arrangement of same-sign gauge-charges, centered on a hexagonal ring with branches of arbitrary length. The ring carries a clockwise or counterclockwise circular flow of magnetisation. This emergent toroidal degrees of freedom provides a possibility for time reversal symmetry breaking with possible relevance to the spontaneous Hall effect observed in Pr2Ir2O7.

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Section: Numerical Setup For Field Quenchessupporting

confidence: 74%

Section: Model and Summary Of Main Resultsmentioning

confidence: 99%

Out-of-equilibrium dynamics and extended textures of topological defects in spin ice

et al. 2016

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“…However, in order to study the general properties of the Coulomb spin liquid coexisting with magnetic order, we do not want to eliminate any configuration a priori. In presence of "4 in / 4 out" tetrahedra, the FCSL is a priori unstable with only nearest-neighbour Ising spin-spin coupling and dipolar interactions 22,23 . But it can be stabilized for example via four-body interactions…”

Section: Fig 2 Thementioning

confidence: 99%

“…Our goal in this paper is to study what happens when a Coulomb spin liquid co-exists with long-range order on the pyrochlore lattice [21][22][23] . In particular, based on the Helmholtz decomposition of Fig.…”

mentioning

confidence: 99%

Monopole Holes in a Partially Ordered Spin Liquid

Jaubert

2015

SPIN

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If spin liquids have been famously defined by what they are not, i.e. ordered, the past years have seen the frontier between order and spin liquid starting to fade, with a growing number of materials whose low-temperature physics cannot be explained without co-existence of (partial) magnetic order and spin fluctuations. Here we study an example of such co-existence in the presence of magnetic dipolar interactions, related to spin ice, where the order is long range and the fluctuations support a Coulomb gauge field. Topological defects are effectively coupled via energetic and entropic Coulomb interactions, the latter one being stronger than for the spin-ice ground state. Depending on whether these defects break the divergence-free condition of the Coulomb gauge field or the long-range order, they are respectively categorized as monopoles -as in spin ice -or monopole holes, in analogy with electron holes in semiconductors. The long-range order plays the role of a fully-occupied valence band, while the Coulomb spin liquid can be seen as an empty conducting band. These results are discussed in the context of other lattices and models which support a similar co-existence of Coulomb gauge field and long-range order. We conclude this work by explaining how dipolar interactions lift the spin liquid degeneracy at very low energy scale by maximizing the number of flippable plaquettes, in light of the equivalent quantum dimer model.The possibility to recast the collective behavior of electrons and atoms as elegant emergent phenomena is probably one of the most fascinating aspect of condensed matter. The emergence of quasi-particles does not only allow for a deeper understanding of the problem at hand but has also often led to surprising connections across physics, as recently illustrated by photon-like magnetic excitations in quantum spin ice 1-4 . Such approach takes an enhanced flavor when the particle has not yet been observed at high energy, or may not exist. This is for example the case for Majorana fermions observed in nanowires coupled to superconductors 5 , and for magnetic monopoles and their underlying Coulomb gauge field 6 .Coulomb gauge theories have emerged from a variety of discrete models, on the kagome lattice 7 , in fully-packed loop models 8 , itinerant-electron systems at partial-filling 9-11 and chemically disordered materials such as CsNiCrF 6 12 . We refer the interested reader to the excellent review by Chris Henley on this topic 13 . But its most famous experimental realization has probably been observed in the classical spin liquid ground state of spin ice materials Dy 2 Ti 2 O 7 and Ho 2 Ti 2 O 7 , where topological excitations take the form of magnetic monopoles effectively interacting via long-range Coulomb interactions.Interestingly, a Coulomb phase is not incompatible with partial magnetic order. For example, the stability of a Coulomb ferromagnet has been discussed in the context of the generalized Quantum Spin Ice model 14,15 and observed over a finite temperature window in a classical spin...

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“…In spite of this, at low fields and temperatures we expect to find a crystal of double charges with the zinc-blende structure. This "all-spins-in-all-spins-out" structure is stabilised not by charge-charge interactions, but due to the constraints imposed by the spins that make these charges [12]. For h h inf (which stabilises a disordered ground state of single monopoles) the situation differs from what it would be trivially expected.…”

Section: Nearest-neighbours Interactions (D = 0)mentioning

confidence: 87%

Monte Carlo study on the detection of classical order by disorder in real antiferromagnetic Ising pyrochlores

Guruciaga

Borzi

2019

Phys. Rev. B

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We use Monte Carlo simulations to evaluate the feasibility of detecting thermal order by disorder in real antiferromagnetic Ising pyrochlores, frustrated by a magnetic field applied in the [110] direction. Building on an ideal system with only nearest-neighbour exchange interactions and a perfectly oriented field, we consider the effects of dipolar interactions and field misalignment. Our approach is special in that it relies more in the possibility to switch on and off the entropic drive towards order than in the absence of (or immunity to) a particular perturbation. It can then be applied, in principle, to other uncontrolled interactions expected to be naturally present in real magnetic materials. We establish the conditions under which entropic effects can be discerned from an interaction drive towards order, show how to use neutron scattering as a means to unveil this mechanism, and discuss possible materials where to test these ideas.

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Monopole ordered phases in dipolar and nearest-neighbors Ising pyrochlore: From spin ice to the all-in–all-out antiferromagnet

Cited by 26 publications

References 31 publications

Out-of-equilibrium dynamics and extended textures of topological defects in spin ice

Out-of-equilibrium dynamics and extended textures of topological defects in spin ice

Monopole Holes in a Partially Ordered Spin Liquid

Monte Carlo study on the detection of classical order by disorder in real antiferromagnetic Ising pyrochlores

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