scholarly journals Quantum phases and spin liquid properties of 1T-TaS2

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Samuel Mañas-Valero ◽  
Benjamin M. Huddart ◽  
Tom Lancaster ◽  
Eugenio Coronado ◽  
Francis L. Pratt
Keyword(s):  
Muon Spin ◽  
Density Wave ◽  
Wave Structure ◽  
Quantum Spin ◽  
Spin Liquid ◽  
Topological Order ◽  
Spin Liquids ◽  
Temperature Dependent ◽  
Quantum Phases ◽  
Frustrated Spin

AbstractQuantum materials exhibiting magnetic frustration are connected to diverse phenomena, including high Tc superconductivity, topological order, and quantum spin liquids (QSLs). A QSL is a quantum phase (QP) related to a quantum-entangled fluid-like state of matter. Previous experiments on QSL candidate materials are usually interpreted in terms of a single QP, although theories indicate that many distinct QPs are closely competing in typical frustrated spin models. Here we report on combined temperature-dependent muon spin relaxation and specific heat measurements for the triangular-lattice QSL candidate material 1T-TaS2 that provide evidence for competing QPs. The measured properties are assigned to arrays of individual QSL layers within the layered charge density wave structure of 1T-TaS2 and their characteristic parameters can be interpreted as those of distinct Z2 QSL phases. The present results reveal that a QSL description can extend beyond the lowest temperatures, offering an additional perspective in the search for such materials.

scholarly journals Correlation holes and slow dynamics induced by fractional statistics in gapped quantum spin liquids

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Oliver Hart ◽  
Yuan Wan ◽  
Claudio Castelnovo
Keyword(s):  
Transport Properties ◽  
Realistic Model ◽  
Feedback Mechanism ◽  
Quantum Spin ◽  
Spin Liquid ◽  
Spin Liquids ◽  
Slow Dynamics ◽  
Temperature Dependent ◽  
Quantum Spin Liquids ◽  
Quantum Spin Liquid

AbstractRealistic model Hamiltonians for quantum spin liquids frequently exhibit a large separation of energy scales between their elementary excitations. At intermediate, experimentally relevant temperatures, some excitations are sparse and hop coherently, whereas others are thermally incoherent and dense. Here, we study the interplay of two such species of quasiparticle, dubbed spinons and visons, which are subject to nontrivial mutual statistics – one of the hallmarks of quantum spin liquid behaviour. Our results for $${{\mathbb{Z}}}_{2}$$ Z 2 quantum spin liquids show an intriguing feedback mechanism, akin to the Nagaoka effect, whereby spinons become localised on temperature-dependent patches of expelled visons. This phenomenon has important consequences for the thermodynamic and transport properties of the system, as well as for its response to quenches in temperature. We argue that these effects can be measured in experiments and may provide viable avenues for obtaining signatures of quantum spin liquid behaviour.

scholarly journals Dichotomy in temporal and thermal spin correlations observed in the breathing pyrochlore LiGa1−xInxCr4O8

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
S. Lee ◽  
S.-H. Do ◽  
W. Lee ◽  
Y. S. Choi ◽  
J. van Tol ◽  
...  
Keyword(s):  
Time Scale ◽  
Spin Dynamics ◽  
Muon Spin ◽  
Quantum Spin ◽  
Spin Liquid ◽  
Fast Time ◽  
Spin Liquids ◽  
Magnetic Ground State ◽  
Spin Correlations ◽  
Magnetic Specific Heat

AbstractA breathing pyrochlore system is predicted to host a variety of quantum spin liquids. Despite tremendous experimental and theoretical efforts, such sought-after states remain elusive as perturbation terms and lattice distortions lead to magnetic order. Here, we utilize bond alternation and disorder to tune a magnetic ground state in the Cr-based breathing pyrochlore LiGa1−xInxCr4O8. By combining thermodynamic and magnetic resonance techniques, we provide experimental signatures of a spin-liquid-like state in x = 0.8, namely, a nearly T2-dependent magnetic specific heat and persistent spin dynamics by muon spin relaxation (μSR). Moreover, 7Li NMR, ZF-μSR, and ESR unveil the temporal and thermal dichotomy of spin correlations: a tetramer singlet on a slow time scale vs. a spin-liquid-like state on a fast time scale. Our results showcase that a bond disorder in the breathing pyrochlore offers a promising route to disclose exotic magnetic phases.

scholarly journals Emergent spin-liquid-like state in the bond-disordered breathing pyrochlore

2020 ◽  
Author(s):  
Suheon Lee ◽  
Seunghwan Do ◽  
W.-J. Lee ◽  
Y.-S. Choi ◽  
Johan Van Tol ◽  
...  
Keyword(s):  
Nearest Neighbor ◽  
Spin Dynamics ◽  
Muon Spin ◽  
Quantum Spin ◽  
Spin Fluctuations ◽  
Spin Liquid ◽  
Spin Liquids ◽  
Magnetic Ground State ◽  
Magnetic Specific Heat ◽  
State Of Matter

Abstract A breathing pyrochlore system is predicted to host a variety of quantum spin liquids. However, perturbations beyond nearest-neighbor Heisenberg interaction are an obstacle to identifying such exotic states. Here, we utilize a bond-alternating disorder to tune a magnetic ground state in the Cr-based breathing pyrochlore. By combining thermodynamic and magnetic resonance techniques, we provide experimental signatures of a spin-liquid-like state in LiGa1-xInxCr4O8 (x=0.2), namely, a nearly T2-dependent magnetic specific heat and a persistent spin dynamics by muon spin relaxation (μSR). Moreover, 7Li NMR, ZF-μSR, and ESR unveil the dichotomic nature of both temporal and thermal spin fluctuations: slowly fluctuating tetramer singlets at high temperatures and a fast fluctuating spin-liquid-like state at low temperatures. Our results suggest that a bond disorder in the breathing pyrochlore offers a new route to achieve an unexplored state of matter.

scholarly journals Quantum spin liquids

Science ◽  
2020 ◽  
Vol 367 (6475) ◽  
pp. eaay0668 ◽  
Author(s):  
C. Broholm ◽  
R. J. Cava ◽  
S. A. Kivelson ◽  
D. G. Nocera ◽  
M. R. Norman ◽  
...  
Keyword(s):  
Ground State ◽  
Quantum Spin ◽  
Spin Liquid ◽  
Spin Liquids ◽  
Quantum Phases ◽  
Quantum Spin Liquids ◽  
The Past ◽  
Quantum Spin Liquid ◽  
Single Material ◽  
Topological Character

Spin liquids are quantum phases of matter with a variety of unusual features arising from their topological character, including “fractionalization”—elementary excitations that behave as fractions of an electron. Although there is not yet universally accepted experimental evidence that establishes that any single material has a spin liquid ground state, in the past few years a number of materials have been shown to exhibit distinctive properties that are expected of a quantum spin liquid. Here, we review theoretical and experimental progress in this area.

scholarly journals Quantum loop states in spin-orbital models on the honeycomb lattice

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lucile Savary
Keyword(s):  
Realistic Model ◽  
Quantum Spin ◽  
Honeycomb Lattice ◽  
Spin Liquids ◽  
Spin Orbital ◽  
Experimental Realization ◽  
Quantum Phases ◽  
Quantum Spin Liquids ◽  
Quantum Spin Liquid ◽  
Symmetry Protected

AbstractThe search for truly quantum phases of matter is a center piece of modern research in condensed matter physics. Quantum spin liquids, which host large amounts of entanglement—an entirely quantum feature where one part of a system cannot be measured without modifying the rest—are exemplars of such phases. Here, we devise a realistic model which relies upon the well-known Haldane chain phase, i.e. the phase of spin-1 chains which host fractional excitations at their ends, akin to the hallmark excitations of quantum spin liquids. We tune our model to exactly soluble points, and find that the ground state realizes Haldane chains whose physical supports fluctuate, realizing both quantum spin liquid like and symmetry-protected topological phases. Crucially, this model is expected to describe actual materials, and we provide a detailed set of material-specific constraints which may be readily used for an experimental realization.

scholarly journals Symmetry-enriched quantum spin liquids in (3 + 1)d

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Po-Shen Hsin ◽  
Alex Turzillo
Keyword(s):  
Gauge Theory ◽  
Gauge Field ◽  
Quantum Spin ◽  
Global Symmetry ◽  
Spin Liquids ◽  
Systematic Method ◽  
Bosonic Field ◽  
Quantum Phases ◽  
Symmetry Protected ◽  
Weyl Fermions

Abstract We use the intrinsic one-form and two-form global symmetries of (3+1)d bosonic field theories to classify quantum phases enriched by ordinary (0-form) global symmetry. Different symmetry-enriched phases correspond to different ways of coupling the theory to the background gauge field of the ordinary symmetry. The input of the classification is the higher-form symmetries and a permutation action of the 0-form symmetry on the lines and surfaces of the theory. From these data we classify the couplings to the background gauge field by the 0-form symmetry defects constructed from the higher-form symmetry defects. For trivial two-form symmetry the classification coincides with the classification for symmetry fractionalizations in (2 + 1)d. We also provide a systematic method to obtain the symmetry protected topological phases that can be absorbed by the coupling, and we give the relative ’t Hooft anomaly for different couplings. We discuss several examples including the gapless pure U(1) gauge theory and the gapped Abelian finite group gauge theory. As an application, we discover a tension with a conjectured duality in (3 + 1)d for SU(2) gauge theory with two adjoint Weyl fermions.

scholarly journals Entanglement signatures of emergent Dirac fermions: Kagome spin liquid and quantum criticality

2018 ◽  
Vol 4 (11) ◽  
pp. eaat5535 ◽  
Author(s):  
Wei Zhu ◽  
Xiao Chen ◽  
Yin-Chen He ◽  
William Witczak-Krempa
Keyword(s):  
Entanglement Entropy ◽  
Quantum Critical Point ◽  
Quantum Spin ◽  
Spin Liquid ◽  
Dirac Fermions ◽  
Spin Liquids ◽  
Density Matrix Renormalization ◽  
Dirac Semimetal ◽  
A Charge ◽  
Aharonov Bohm

Quantum spin liquids (QSLs) are exotic phases of matter that host fractionalized excitations. It is difficult for local probes to characterize QSL, whereas quantum entanglement can serve as a powerful diagnostic tool due to its nonlocality. The kagome antiferromagnetic Heisenberg model is one of the most studied and experimentally relevant models for QSL, but its solution remains under debate. Here, we perform a numerical Aharonov-Bohm experiment on this model and uncover universal features of the entanglement entropy. By means of the density matrix renormalization group, we reveal the entanglement signatures of emergent Dirac spinons, which are the fractionalized excitations of the QSL. This scheme provides qualitative insights into the nature of kagome QSL and can be used to study other quantum states of matter. As a concrete example, we also benchmark our methods on an interacting quantum critical point between a Dirac semimetal and a charge-ordered phase.

scholarly journals Quantum Spin Liquids in Frustrated Spin-1 Diamond Antiferromagnets

2018 ◽  
Vol 120 (5) ◽  
Author(s):  
Finn Lasse Buessen ◽  
Max Hering ◽  
Johannes Reuther ◽  
Simon Trebst
Keyword(s):  
Quantum Spin ◽  
Spin Liquids ◽  
Quantum Spin Liquids ◽  
Frustrated Spin

scholarly journals Quantum spin-liquid states in an organic magnetic layer and molecular rotor hybrid

2020 ◽  
Vol 117 (47) ◽  
pp. 29555-29560
Author(s):  
Péter Szirmai ◽  
Cécile Mézière ◽  
Guillaume Bastien ◽  
Pawel Wzietek ◽  
Patrick Batail ◽  
...  
Keyword(s):  
Magnetic Measurements ◽  
Magnetic Layer ◽  
Quantum Spin ◽  
Spin Liquid ◽  
Organic Crystals ◽  
Spin Liquids ◽  
Molecular Rotor ◽  
Low Dimensionality ◽  
Liquid States ◽  
Quantum Spin Liquid

The exotic properties of quantum spin liquids (QSLs) have continually been of interest since Anderson’s 1973 ground-breaking idea. Geometrical frustration, quantum fluctuations, and low dimensionality are the most often evoked material’s characteristics that favor the long-range fluctuating spin state without freezing into an ordered magnet or a spin glass at low temperatures. Among the few known QSL candidates, organic crystals have the advantage of having rich chemistry capable of finely tuning their microscopic parameters. Here, we demonstrate the emergence of a QSL state in [EDT-TTF-CONH2]2+[BABCO−] (EDT-BCO), where the EDT molecules with spin-1/2 on a triangular lattice form layers which are separated by a sublattice of BCO molecular rotors. By several magnetic measurements, we show that the subtle random potential of frozen BCO Brownian rotors suppresses magnetic order down to the lowest temperatures. Our study identifies the relevance of disorder in the stabilization of QSLs.

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