1
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Yue WC, Yuan Z, Huang P, Sun Y, Gao T, Lyu YY, Tu X, Dong S, He L, Dong Y, Cao X, Kang L, Wang H, Wu P, Nisoli C, Wang YL. Toroidic phase transitions in a direct-kagome artificial spin ice. NATURE NANOTECHNOLOGY 2024; 19:1101-1107. [PMID: 38684808 DOI: 10.1038/s41565-024-01666-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 03/27/2024] [Indexed: 05/02/2024]
Abstract
Ferrotoroidicity-the fourth form of primary ferroic order-breaks both space and time-inversion symmetry. So far, direct observation of ferrotoroidicity in natural materials remains elusive, which impedes the exploration of ferrotoroidic phase transitions. Here we overcome the limitations of natural materials using an artificial nanomagnet system that can be characterized at the constituent level and at different effective temperatures. We design a nanomagnet array as to realize a direct-kagome spin ice. This artificial spin ice exhibits robust toroidal moments and a quasi-degenerate ground state with two distinct low-temperature toroidal phases: ferrotoroidicity and paratoroidicity. Using magnetic force microscopy and Monte Carlo simulation, we demonstrate a phase transition between ferrotoroidicity and paratoroidicity, along with a cross-over to a non-toroidal paramagnetic phase. Our quasi-degenerate artificial spin ice in a direct-kagome structure provides a model system for the investigation of magnetic states and phase transitions that are inaccessible in natural materials.
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Affiliation(s)
- Wen-Cheng Yue
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China
- Purple Mountain Laboratories, Nanjing, China
- Research Institute of Superconductor Electronics, Nanjing University, Nanjing, China
| | - Zixiong Yuan
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China
- Purple Mountain Laboratories, Nanjing, China
- Research Institute of Superconductor Electronics, Nanjing University, Nanjing, China
| | - Peiyuan Huang
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China
- Purple Mountain Laboratories, Nanjing, China
- Research Institute of Superconductor Electronics, Nanjing University, Nanjing, China
| | - Yizhe Sun
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China
- National Key Laboratory of Spintronics, Nanjing University, Suzhou, China
| | - Tan Gao
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China
- Purple Mountain Laboratories, Nanjing, China
- Research Institute of Superconductor Electronics, Nanjing University, Nanjing, China
| | - Yang-Yang Lyu
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China
- Purple Mountain Laboratories, Nanjing, China
- Research Institute of Superconductor Electronics, Nanjing University, Nanjing, China
| | - Xuecou Tu
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China
- Purple Mountain Laboratories, Nanjing, China
- Research Institute of Superconductor Electronics, Nanjing University, Nanjing, China
| | - Sining Dong
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China.
- Research Institute of Superconductor Electronics, Nanjing University, Nanjing, China.
- National Key Laboratory of Spintronics, Nanjing University, Suzhou, China.
| | - Liang He
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China
- National Key Laboratory of Spintronics, Nanjing University, Suzhou, China
| | - Ying Dong
- College of Metrology Measurement and Instrument, China Jiliang University, Hangzhou, China
| | - Xun Cao
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China
| | - Lin Kang
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China
- Research Institute of Superconductor Electronics, Nanjing University, Nanjing, China
| | - Huabing Wang
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China.
- Purple Mountain Laboratories, Nanjing, China.
- Research Institute of Superconductor Electronics, Nanjing University, Nanjing, China.
| | - Peiheng Wu
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China
- Purple Mountain Laboratories, Nanjing, China
- Research Institute of Superconductor Electronics, Nanjing University, Nanjing, China
| | - Cristiano Nisoli
- Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, NM, USA.
| | - Yong-Lei Wang
- School of Electronic Science and Engineering, Nanjing University, Nanjing, China.
- Purple Mountain Laboratories, Nanjing, China.
- Research Institute of Superconductor Electronics, Nanjing University, Nanjing, China.
- National Key Laboratory of Spintronics, Nanjing University, Suzhou, China.
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2
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Lopez-Bezanilla A, Raymond J, Boothby K, Carrasquilla J, Nisoli C, King AD. Kagome qubit ice. Nat Commun 2023; 14:1105. [PMID: 36849545 PMCID: PMC9970994 DOI: 10.1038/s41467-023-36760-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 02/13/2023] [Indexed: 03/01/2023] Open
Abstract
Topological phases of spin liquids with constrained disorder can host a kinetics of fractionalized excitations. However, spin-liquid phases with distinct kinetic regimes have proven difficult to observe experimentally. Here we present a realization of kagome spin ice in the superconducting qubits of a quantum annealer, and use it to demonstrate a field-induced kinetic crossover between spin-liquid phases. Employing fine control over local magnetic fields, we show evidence of both the Ice-I phase and an unconventional field-induced Ice-II phase. In the latter, a charge-ordered yet spin-disordered topological phase, the kinetics proceeds via pair creation and annihilation of strongly correlated, charge conserving, fractionalized excitations. As these kinetic regimes have resisted characterization in other artificial spin ice realizations, our results demonstrate the utility of quantum-driven kinetics in advancing the study of topological phases of spin liquids.
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Affiliation(s)
- Alejandro Lopez-Bezanilla
- grid.148313.c0000 0004 0428 3079Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 USA
| | | | | | - Juan Carrasquilla
- grid.17063.330000 0001 2157 2938Vector Institute, University of Toronto, Toronto, ON M5G 1M1 Canada ,grid.46078.3d0000 0000 8644 1405Department of Physics and Astronomy, University of Waterloo, Waterloo, ON N2L 3G1 Canada
| | - Cristiano Nisoli
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.
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3
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Generalized Gibbs Phase Rule and Multicriticality Applied to Magnetic Systems. ENTROPY 2021; 24:e24010063. [PMID: 35052088 PMCID: PMC8775071 DOI: 10.3390/e24010063] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 12/20/2021] [Accepted: 12/27/2021] [Indexed: 11/17/2022]
Abstract
A generalization of the original Gibbs phase rule is proposed in order to study the presence of single phases, multiphase coexistence, and multicritical phenomena in lattice spin magnetic models. The rule is based on counting the thermodynamic number of degrees of freedom, which strongly depends on the external fields needed to break the ground state degeneracy of the model. The phase diagrams of some spin Hamiltonians are analyzed according to this general phase rule, including general spin Ising and Blume–Capel models, as well as q-state Potts models. It is shown that by properly taking into account the intensive fields of the model in study, the generalized Gibbs phase rule furnishes a good description of the possible topology of the corresponding phase diagram. Although this scheme is unfortunately not able to locate the phase boundaries, it is quite useful to at least provide a good description regarding the possible presence of critical and multicritical surfaces, as well as isolated multicritical points.
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4
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Rodríguez-Gallo C, Ortiz-Ambriz A, Tierno P. Topological Boundary Constraints in Artificial Colloidal Ice. PHYSICAL REVIEW LETTERS 2021; 126:188001. [PMID: 34018772 DOI: 10.1103/physrevlett.126.188001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 03/17/2021] [Accepted: 04/07/2021] [Indexed: 06/12/2023]
Abstract
The effect of boundaries and how these can be used to influence the bulk behavior in geometrically frustrated systems are both long-standing puzzles, often relegated to a secondary role. Here, we use numerical simulations and "proof of concept" experiments to demonstrate that boundaries can be engineered to control the bulk behavior in a colloidal artificial ice. We show that an antiferromagnetic frontier forces the system to rapidly reach the ground state (GS), as opposed to the commonly implemented open or periodic boundary conditions. We also show that strategically placing defects at the corners generates novel bistable states, or topological strings, which result from competing GS regions in the bulk. Our results could be generalized to other frustrated micro- and nanostructures where boundary conditions may be engineered with lithographic techniques.
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Affiliation(s)
- Carolina Rodríguez-Gallo
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, 08028, Barcelona, Spain
- Universitat de Barcelona Institute of Complex Systems (UBICS), Universitat de Barcelona, 08028, Barcelona, Spain
| | - Antonio Ortiz-Ambriz
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, 08028, Barcelona, Spain
- Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, 08028, Barcelona, Spain
| | - Pietro Tierno
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, 08028, Barcelona, Spain
- Universitat de Barcelona Institute of Complex Systems (UBICS), Universitat de Barcelona, 08028, Barcelona, Spain
- Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, 08028, Barcelona, Spain
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5
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Gartside JC, Vanstone A, Dion T, Stenning KD, Arroo DM, Kurebayashi H, Branford WR. Reconfigurable magnonic mode-hybridisation and spectral control in a bicomponent artificial spin ice. Nat Commun 2021; 12:2488. [PMID: 33941786 PMCID: PMC8093262 DOI: 10.1038/s41467-021-22723-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 03/22/2021] [Indexed: 02/02/2023] Open
Abstract
Strongly-interacting nanomagnetic arrays are finding increasing use as model host systems for reconfigurable magnonics. The strong inter-element coupling allows for stark spectral differences across a broad microstate space due to shifts in the dipolar field landscape. While these systems have yielded impressive initial results, developing rapid, scaleable means to access a broad range of spectrally-distinct microstates is an open research problem. We present a scheme whereby square artificial spin ice is modified by widening a 'staircase' subset of bars relative to the rest of the array, allowing preparation of any ordered vertex state via simple global-field protocols. Available microstates range from the system ground-state to high-energy 'monopole' states, with rich and distinct microstate-specific magnon spectra observed. Microstate-dependent mode-hybridisation and anticrossings are observed at both remanence and in-field with dynamic coupling strength tunable via microstate-selection. Experimental coupling strengths are found up to g/2π = 0.16 GHz. Microstate control allows fine mode-frequency shifting, gap creation and closing, and active mode number selection.
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Affiliation(s)
| | - Alex Vanstone
- Blackett Laboratory, Imperial College London, London, UK
| | - Troy Dion
- Blackett Laboratory, Imperial College London, London, UK
- London Centre for Nanotechnology, University College London, London, UK
| | | | - Daan M Arroo
- London Centre for Nanotechnology, University College London, London, UK
- Department of Materials, Imperial College London, London, UK
| | | | - Will R Branford
- Blackett Laboratory, Imperial College London, London, UK
- London Centre for Nanotechnology, Imperial College London, London, UK
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6
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Duzgun A, Nisoli C. Skyrmion Spin Ice in Liquid Crystals. PHYSICAL REVIEW LETTERS 2021; 126:047801. [PMID: 33576672 DOI: 10.1103/physrevlett.126.047801] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 10/17/2020] [Accepted: 12/23/2020] [Indexed: 06/12/2023]
Abstract
We propose the first skyrmion spin ice, realized via confined, interacting liquid crystal skyrmions. Skyrmions in a chiral nematic liquid crystal behave as quasiparticles that can be dynamically confined, bound, and created or annihilated individually with ease and precision. We show that these quasiparticles can be employed to realize binary variables that interact to form ice-rule states. Because of their unique versatility, liquid crystal skyrmions can open entirely novel avenues in the field of frustrated systems. More broadly, our findings also demonstrate the viability of liquid crystal skyrmions as elementary degrees of freedom in the design of collective complex behaviors.
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Affiliation(s)
- Ayhan Duzgun
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Cristiano Nisoli
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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7
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Menezes RM, Sardella E, Cabral LRE, de Souza Silva CC. Self-assembled vortex crystals induced by inhomogeneous magnetic textures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:175402. [PMID: 30699395 DOI: 10.1088/1361-648x/ab035a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We investigate the self-assembly of vortices in a type-II superconducting disk subjected to highly nonuniform confining potentials produced by inhomogeneous magnetic textures. Using a series of numerical experiments performed within the Ginzburg-Landau theory, we show that vortices can arrange spontaneously in highly nonuniform, defect-free crystals, reminiscent of conformal lattices, even though the strict conditions for the conformal crystal are not fulfilled. These results contradict continuum-limit theory, which predicts that the order of a nonuniform crystal is unavoidably frustrated by the presence of topological defects. By testing different cooling routes of the superconductor, we observed several different self-assembled configurations, each of which corresponding to one in a set of allowed conformal transformations, which depends on the magnetic and thermal histories of the system.
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Affiliation(s)
- Raí M Menezes
- Departamento de Física, Universidade Federal de Pernambuco, Cidade Universitária, 50670-901, Recife-PE, Brazil
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8
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Libál A, Lee DY, Ortiz-Ambriz A, Reichhardt C, Reichhardt CJO, Tierno P, Nisoli C. Ice rule fragility via topological charge transfer in artificial colloidal ice. Nat Commun 2018; 9:4146. [PMID: 30297820 PMCID: PMC6175946 DOI: 10.1038/s41467-018-06631-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Accepted: 09/05/2018] [Indexed: 11/09/2022] Open
Abstract
Artificial particle ices are model systems of constrained, interacting particles. They have been introduced theoretically to study ice-manifolds emergent from frustration, along with domain wall and grain boundary dynamics, doping, pinning-depinning, controlled transport of topological defects, avalanches, and memory effects. Recently such particle-based ices have been experimentally realized with vortices in nano-patterned superconductors or gravitationally trapped colloids. Here we demonstrate that, although these ices are generally considered equivalent to magnetic spin ices, they can access a novel spectrum of phenomenologies that are inaccessible to the latter. With experiments, theory and simulations we demonstrate that in mixed coordination geometries, entropy-driven negative monopoles spontaneously appear at a density determined by the vertex-mixture ratio. Unlike its spin-based analogue, the colloidal system displays a "fragile ice" manifold, where local energetics oppose the ice rule, which is instead enforced through conservation of the global topological charge. The fragile colloidal ice, stabilized by topology, can be spontaneously broken by topological charge transfer.
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Affiliation(s)
- András Libál
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.,Mathematics and Computer Science Department, Babeş-Bolyai University, Cluj, 400084, Romania
| | - Dong Yun Lee
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, Barcelona, 08028, España
| | - Antonio Ortiz-Ambriz
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, Barcelona, 08028, España.,Institut de Nanociència i Nanotecnologia, Universitat de Barcelona, Barcelona, 08028, Spain
| | - Charles Reichhardt
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | | | - Pietro Tierno
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, Barcelona, 08028, España.,Universitat de Barcelona Institute of Complex Systems (UBICS), Universitat de Barcelona, Barcelona, 08028, Spain.,Institut de Nanociència i Nanotecnologia, Universitat de Barcelona, Barcelona, 08028, Spain
| | - Cristiano Nisoli
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA. .,Institute for Materials Science, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.
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9
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Tunable and switchable magnetic dipole patterns in nanostructured superconductors. Nat Commun 2018; 9:2576. [PMID: 29968732 PMCID: PMC6030140 DOI: 10.1038/s41467-018-05045-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 06/08/2018] [Indexed: 11/08/2022] Open
Abstract
Design and manipulation of magnetic moment arrays have been at the focus of studying the interesting cooperative physical phenomena in various magnetic systems. However, long-range ordered magnetic moments are rather difficult to achieve due to the excited states arising from the relatively weak exchange interactions between the localized moments. Here, using a nanostructured superconductor, we investigate a perfectly ordered magnetic dipole pattern with the magnetic poles having the same distribution as the magnetic charges in an artificial spin ice. The magnetic states can simply be switched on/off by applying a current flowing through nanopatterned area. Moreover, by coupling magnetic dipoles with the pinned vortex lattice, we are able to erase the positive/negative poles, resulting in a magnetic dipole pattern of only one polarity, analogous to the recently predicted vortex ice. These switchable and tunable magnetic dipole patterns open pathways for the study of exotic ordering phenomena in magnetic systems.
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10
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Wang YL, Ma X, Xu J, Xiao ZL, Snezhko A, Divan R, Ocola LE, Pearson JE, Janko B, Kwok WK. Switchable geometric frustration in an artificial-spin-ice-superconductor heterosystem. NATURE NANOTECHNOLOGY 2018; 13:560-565. [PMID: 29892018 DOI: 10.1038/s41565-018-0162-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 05/03/2018] [Indexed: 06/08/2023]
Abstract
Geometric frustration emerges when local interaction energies in an ordered lattice structure cannot be simultaneously minimized, resulting in a large number of degenerate states. The numerous degenerate configurations may lead to practical applications in microelectronics1, such as data storage, memory and logic2. However, it is difficult to achieve very high degeneracy, especially in a two-dimensional system3,4. Here, we showcase in situ controllable geometric frustration with high degeneracy in a two-dimensional flux-quantum system. We create this in a superconducting thin film placed underneath a reconfigurable artificial-spin-ice structure5. The tunable magnetic charges in the artificial-spin-ice strongly interact with the flux quanta in the superconductor, enabling switching between frustrated and crystallized flux quanta states. The different states have measurable effects on the superconducting critical current profile, which can be reconfigured by precise selection of the spin-ice magnetic state through the application of an external magnetic field. We demonstrate the applicability of these effects by realizing a reprogrammable flux quanta diode. The tailoring of the energy landscape of interacting 'particles' using artificial-spin-ices provides a new paradigm for the design of geometric frustration, which could illuminate a path to control new functionalities in other material systems, such as magnetic skyrmions6, electrons and holes in two-dimensional materials7,8, and topological insulators9, as well as colloids in soft materials10-13.
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Affiliation(s)
- Yong-Lei Wang
- Materials Science Division, Argonne National Laboratory, Argonne, IL, USA.
- Department of Physics, University of Notre Dame, Notre Dame, IN, USA.
- Research Institute of Superconductor Electronics, School of Electronic Science and Engineering, Nanjing University, Nanjing, China.
| | - Xiaoyu Ma
- Department of Physics, University of Notre Dame, Notre Dame, IN, USA
| | - Jing Xu
- Materials Science Division, Argonne National Laboratory, Argonne, IL, USA
- Department of Physics, Northern Illinois University, DeKalb, IL, USA
| | - Zhi-Li Xiao
- Materials Science Division, Argonne National Laboratory, Argonne, IL, USA.
- Department of Physics, Northern Illinois University, DeKalb, IL, USA.
| | - Alexey Snezhko
- Materials Science Division, Argonne National Laboratory, Argonne, IL, USA
| | - Ralu Divan
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, IL, USA
| | - Leonidas E Ocola
- Center for Nanoscale Materials, Argonne National Laboratory, Argonne, IL, USA
- IBM Thomas J. Watson Research Center, Yorktown Heights, NY, USA
| | - John E Pearson
- Materials Science Division, Argonne National Laboratory, Argonne, IL, USA
| | - Boldizsar Janko
- Department of Physics, University of Notre Dame, Notre Dame, IN, USA.
| | - Wai-Kwong Kwok
- Materials Science Division, Argonne National Laboratory, Argonne, IL, USA
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11
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Nisoli C. Unexpected Phenomenology in Particle-Based Ice Absent in Magnetic Spin Ice. PHYSICAL REVIEW LETTERS 2018; 120:167205. [PMID: 29756919 DOI: 10.1103/physrevlett.120.167205] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Indexed: 06/08/2023]
Abstract
While particle-based ices are often considered essentially equivalent to magnet-based spin ices, the two differ essentially in frustration and energetics. We show that at equilibrium particle-based ices correspond exactly to spin ices coupled to a background field. In trivial geometries, such a field has no effect, and the two systems are indeed thermodynamically equivalent. In other cases, however, the field controls a richer phenomenology, absent in magnetic ices, and still largely unexplored: ice rule fragility, topological charge transfer, radial polarization, decimation induced disorder, and glassiness.
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Affiliation(s)
- Cristiano Nisoli
- Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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12
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Libál A, Nisoli C, Reichhardt CJO, Reichhardt C. Inner Phases of Colloidal Hexagonal Spin Ice. PHYSICAL REVIEW LETTERS 2018; 120:027204. [PMID: 29376707 DOI: 10.1103/physrevlett.120.027204] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Indexed: 06/07/2023]
Abstract
Using numerical simulations that mimic recent experiments on hexagonal colloidal ice, we show that colloidal hexagonal artificial spin ice exhibits an inner phase within its ice state that has not been observed previously. Under increasing colloid-colloid repulsion, the initially paramagnetic system crosses into a disordered ice regime, then forms a topologically charge ordered state with disordered colloids, and finally reaches a threefold degenerate, ordered ferromagnetic state. This is reminiscent of, yet distinct from, the inner phases of the magnetic kagome spin ice analog. The difference in the inner phases of the two systems is explained by their difference in energetics and frustration.
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Affiliation(s)
- A Libál
- Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
- Mathematics and Computer Science Department, Babeş-Bolyai University, Cluj 400084, Romania
| | - C Nisoli
- Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - C J O Reichhardt
- Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - C Reichhardt
- Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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13
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Wang YL, Xiao ZL, Snezhko A, Xu J, Ocola LE, Divan R, Pearson JE, Crabtree GW, Kwok WK. Rewritable artificial magnetic charge ice. Science 2016; 352:962-6. [DOI: 10.1126/science.aad8037] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 04/13/2016] [Indexed: 11/02/2022]
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14
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Trastoy J, Malnou M, Ulysse C, Bernard R, Bergeal N, Faini G, Lesueur J, Briatico J, Villegas JE. Freezing and thawing of artificial ice by thermal switching of geometric frustration in magnetic flux lattices. NATURE NANOTECHNOLOGY 2014; 9:710-715. [PMID: 25129072 DOI: 10.1038/nnano.2014.158] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 07/02/2014] [Indexed: 06/03/2023]
Abstract
The problem of an ensemble of repulsive particles on a potential-energy landscape is common to many physical systems and has been studied in multiple artificial playgrounds. However, the latter usually involve fixed energy landscapes, thereby impeding in situ investigations of the particles' collective response to controlled changes in the landscape geometry. Here, we experimentally realize a system in which the geometry of the potential-energy landscape can be switched using temperature as the control knob. This realization is based on a high-temperature superconductor in which we engineer a nanoscale spatial modulation of the superconducting condensate. Depending on the temperature, the flux quanta induced by an applied magnetic field see either a geometrically frustrated energy landscape that favours an ice-like flux ordering, or an unfrustrated landscape that yields a periodic flux distribution. This effect is reflected in a dramatic change in the superconductor's magneto-transport. The thermal switching of the energy landscape geometry opens new opportunities for the study of ordering and reorganization in repulsive particle manifolds.
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Affiliation(s)
- J Trastoy
- 1] Unité Mixte de Physique CNRS/Thales, 1 ave. A. Fresnel, 91767 Palaiseau, France [2] Université Paris Sud, 91405 Orsay, France
| | - M Malnou
- LPEM, ESPCI-CNRS-UPMC, 10 rue Vauquelin 75231 Paris, France
| | - C Ulysse
- CNRS, Phynano Team, Laboratoire de Photonique et de Nanostructures, route de Nozay, 91460 Marcoussis, France
| | - R Bernard
- 1] Unité Mixte de Physique CNRS/Thales, 1 ave. A. Fresnel, 91767 Palaiseau, France [2] Université Paris Sud, 91405 Orsay, France
| | - N Bergeal
- LPEM, ESPCI-CNRS-UPMC, 10 rue Vauquelin 75231 Paris, France
| | - G Faini
- CNRS, Phynano Team, Laboratoire de Photonique et de Nanostructures, route de Nozay, 91460 Marcoussis, France
| | - J Lesueur
- LPEM, ESPCI-CNRS-UPMC, 10 rue Vauquelin 75231 Paris, France
| | - J Briatico
- 1] Unité Mixte de Physique CNRS/Thales, 1 ave. A. Fresnel, 91767 Palaiseau, France [2] Université Paris Sud, 91405 Orsay, France
| | - Javier E Villegas
- 1] Unité Mixte de Physique CNRS/Thales, 1 ave. A. Fresnel, 91767 Palaiseau, France [2] Université Paris Sud, 91405 Orsay, France
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15
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Heyderman LJ, Stamps RL. Artificial ferroic systems: novel functionality from structure, interactions and dynamics. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:363201. [PMID: 23948652 DOI: 10.1088/0953-8984/25/36/363201] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Lithographic processing and film growth technologies are continuing to advance, so that it is now possible to create patterned ferroic materials consisting of arrays of sub-1 μm elements with high definition. Some of the most fascinating behaviour of these arrays can be realised by exploiting interactions between the individual elements to create new functionality. The properties of these artificial ferroic systems differ strikingly from those of their constituent components, with novel emergent behaviour arising from the collective dynamics of the interacting elements, which are arranged in specific designs and can be activated by applying magnetic or electric fields. We first focus on artificial spin systems consisting of arrays of dipolar-coupled nanomagnets and, in particular, review the field of artificial spin ice, which demonstrates a wide range of fascinating phenomena arising from the frustration inherent in particular arrangements of nanomagnets, including emergent magnetic monopoles, domains of ordered macrospins, and novel avalanche behaviour. We outline how demagnetisation protocols have been employed as an effective thermal anneal in an attempt to reach the ground state, comment on phenomena that arise in thermally activated systems and discuss strategies for selectively generating specific configurations using applied magnetic fields. We then move on from slow field and temperature driven dynamics to high frequency phenomena, discussing spinwave excitations in the context of magnonic crystals constructed from arrays of patterned magnetic elements. At high frequencies, these arrays are studied in terms of potential applications including magnetic logic, linear and non-linear microwave optics, and fast, efficient switching, and we consider the possibility to create tunable magnonic crystals with artificial spin ice. Finally, we discuss how functional ferroic composites can be incorporated to realise magnetoelectric effects. Specifically, we discuss artificial multiferroics (or multiferroic composites), which hold promise for new applications that involve electric field control of magnetism, or electric and magnetic field responsive devices for high frequency integrated circuit design in microwave and terahertz signal processing. We close with comments on how enhanced functionality can be realised through engineering of nanostructures with interacting ferroic components, creating opportunities for novel spin electronic devices that, for example, make use of the transport of magnetic charges, thermally activated elements, and reprogrammable nanomagnet systems.
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Affiliation(s)
- L J Heyderman
- Laboratory for Mesoscopic Systems, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland.
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Latimer ML, Berdiyorov GR, Xiao ZL, Peeters FM, Kwok WK. Realization of artificial ice systems for magnetic vortices in a superconducting MoGe thin film with patterned nanostructures. PHYSICAL REVIEW LETTERS 2013; 111:067001. [PMID: 23971602 DOI: 10.1103/physrevlett.111.067001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Indexed: 06/02/2023]
Abstract
We report an anomalous matching effect in MoGe thin films containing pairs of circular holes arranged in such a way that four of those pairs meet at each vertex point of a square lattice. A remarkably pronounced fractional matching was observed in the magnetic field dependences of both the resistance and the critical current. At the half matching field the critical current can be even higher than that at zero field. This has never been observed before for vortices in superconductors with pinning arrays. Numerical simulations within the nonlinear Ginzburg-Landau theory reveal a square vortex ice configuration in the ground state at the half matching field and demonstrate similar characteristic features in the field dependence of the critical current, confirming the experimental realization of an artificial ice system for vortices for the first time.
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Affiliation(s)
- M L Latimer
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA
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Libál A, Reichhardt C, Olson Reichhardt CJ. Hysteresis and return-point memory in colloidal artificial spin ice systems. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 86:021406. [PMID: 23005762 DOI: 10.1103/physreve.86.021406] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Revised: 06/22/2012] [Indexed: 06/01/2023]
Abstract
Using computer simulations, we investigate hysteresis loops and return-point memory for artificial square and kagome spin ice systems by cycling an applied bias force and comparing microscopic effective spin configurations throughout the hysteresis cycle. Return-point memory loss is caused by motion of individual defects in kagome ice or of grain boundaries in square ice. In successive cycles, return-point memory is recovered rapidly in kagome ice. Memory is recovered more gradually in square ice due to the extended nature of the grain boundaries. Increasing the amount of quenched disorder increases the defect density but also enhances the return-point memory since the defects become trapped more easily.
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Affiliation(s)
- A Libál
- Faculty of Mathematics and Computer Science, Babes-Bolyai University, RO-400591 Cluj-Napoca, Romania
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Budrikis Z, Morgan JP, Akerman J, Stein A, Politi P, Langridge S, Marrows CH, Stamps RL. Disorder strength and field-driven ground state domain formation in artificial spin ice: experiment, simulation, and theory. PHYSICAL REVIEW LETTERS 2012; 109:037203. [PMID: 22861890 DOI: 10.1103/physrevlett.109.037203] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Indexed: 06/01/2023]
Abstract
Quenched disorder affects how nonequilibrium systems respond to driving. In the context of artificial spin ice, an athermal system comprised of geometrically frustrated classical Ising spins with a twofold degenerate ground state, we give experimental and numerical evidence of how such disorder washes out edge effects and provide an estimate of disorder strength in the experimental system. We prove analytically that a sequence of applied fields with fixed amplitude is unable to drive the system to its ground state from a saturated state. These results should be relevant for other systems where disorder does not change the nature of the ground state.
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Affiliation(s)
- Zoe Budrikis
- School of Physics, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Australia.
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Chern GW, Wu C. Orbital ice: an exact Coulomb phase on the diamond lattice. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 84:061127. [PMID: 22304060 DOI: 10.1103/physreve.84.061127] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Revised: 11/26/2011] [Indexed: 05/31/2023]
Abstract
We demonstrate the existence of an orbital Coulomb phase as the exact ground state of a p-orbital exchange Hamiltonian on the diamond lattice. The Coulomb phase is an emergent state characterized by algebraic dipolar correlations and a gauge structure resulting from local constraints (ice rules) of the underlying lattice models. For most ice models on the pyrochlore lattice, these local constraints are a direct consequence of minimizing the energy of each individual tetrahedron. On the contrary, the orbital ice rules are emergent phenomena resulting from the quantum orbital dynamics. We show that the orbital ice model exhibits an emergent geometrical frustration by mapping the degenerate quantum orbital ground states to the spin-ice states obeying the 2-in-2-out constraints on the pyrochlore lattice. We also discuss possible realization of the orbital ice model in optical lattices with p-band fermionic cold atoms.
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Affiliation(s)
- Gia-Wei Chern
- Department of Physics, University of Wisconsin, Madison, Wisconsin 53706, USA
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Budrikis Z, Politi P, Stamps RL. Diversity enabling equilibration: disorder and the ground state in artificial spin ice. PHYSICAL REVIEW LETTERS 2011; 107:217204. [PMID: 22181919 DOI: 10.1103/physrevlett.107.217204] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Indexed: 05/31/2023]
Abstract
We report a novel approach to the question of whether and how the ground state can be achieved in square artificial spin ices where frustration is incomplete. We identify two sources of randomness that affect the approach to ground state: quenched disorder in the island response to fields and randomness in the sequence of driving fields. Numerical simulations show that quenched disorder can lead to final states with lower energy, and randomness in the sequence of driving fields always lowers the final energy attained by the system. We use a network picture to understand these two effects: disorder in island responses creates new dynamical pathways, and a random sequence of driving fields allows more pathways to be followed.
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Affiliation(s)
- Zoe Budrikis
- School of Physics, The University of Western Australia, Australia.
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Geometric frustration in compositionally modulated ferroelectrics. Nature 2011; 470:513-7. [DOI: 10.1038/nature09752] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Accepted: 12/09/2010] [Indexed: 11/09/2022]
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