Theoretical and experimental developments in quantum spin liquid in geometrically frustrated magnets: a review

2019 ◽  
Vol 55 (6) ◽  
pp. 2257-2290 ◽  
Author(s):  
V. R. Shaginyan ◽  
V. A. Stephanovich ◽  
A. Z. Msezane ◽  
G. S. Japaridze ◽  
J. W. Clark ◽  
...  
Keyword(s):  
Quantum Spin ◽  
Spin Liquid ◽  
Frustrated Magnets ◽  
Geometrically Frustrated ◽  
Quantum Spin Liquid

scholarly journals Thermodynamic, Dynamic, and Transport Properties of Quantum Spin Liquid in Herbertsmithite from an Experimental and Theoretical Point of View

2019 ◽  
Vol 4 (3) ◽  
pp. 75 ◽  
Author(s):  
Vasily R. Shaginyan ◽  
Alfred Z. Msezane ◽  
Miron Ya. Amusia ◽  
John W. Clark ◽  
George S. Japaridze ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Transport Properties ◽  
Optical Conductivity ◽  
Inelastic Neutron Scattering ◽  
Quantum Spin ◽  
Spin Liquid ◽  
Theoretical Point ◽  
Geometrically Frustrated ◽  
State Of Matter ◽  
Quantum Spin Liquid

In our review, we focus on the quantum spin liquid (QSL), defining the thermodynamic, transport, and relaxation properties of geometrically frustrated magnet (insulators) represented by herbertsmithite ZnCu 3 ( OH ) 6 Cl 2 . The review mostly deals with an historical perspective of our theoretical contributions on this subject, based on the theory of fermion condensation closely related to the emergence (due to geometrical frustration) of dispersionless parts in the fermionic quasiparticle spectrum, so-called flat bands. QSL is a quantum state of matter having neither magnetic order nor gapped excitations even at zero temperature. QSL along with heavy fermion metals can form a new state of matter induced by the topological fermion condensation quantum phase transition. The observation of QSL in actual materials such as herbertsmithite is of fundamental significance both theoretically and technologically, as it could open a path to the creation of topologically protected states for quantum information processing and quantum computation. It is therefore of great importance to establish the presence of a gapless QSL state in one of the most prospective materials, herbertsmithite. In this respect, the interpretation of current theoretical and experimental studies of herbertsmithite are controversial in their implications. Based on published experimental data augmented by our theoretical analysis, we present evidence for the the existence of a QSL in the geometrically frustrated insulator herbertsmithite ZnCu 3 ( OH ) 6 Cl 2 , providing a strategy for unambiguous identification of such a state in other materials. To clarify the nature of QSL in herbertsmithite, we recommend measurements of heat transport, low-energy inelastic neutron scattering, and optical conductivity σ ¯ in ZnCu 3 ( OH ) 6 Cl 2 crystals subject to an external magnetic field at low temperatures. Our analysis of the behavior of σ ¯ in herbertsmithite justifies this set of measurements, which can provide a conclusive experimental demonstration of the nature of its spinon-composed quantum spin liquid. Theoretical study of the optical conductivity of herbertsmithite allows us to expose the physical mechanisms responsible for its temperature and magnetic field dependence. We also suggest that artificially or spontaneously introducing inhomogeneity at nanoscale into ZnCu 3 ( OH ) 6 Cl 2 can both stabilize its QSL and simplify its chemical preparation, and can provide for tests that elucidate the role of impurities. We make predictions of the results of specified measurements related to the dynamical, thermodynamic, and transport properties in the case of a gapless QSL.

scholarly journals Quantum spin liquid signatures in Kitaev-like frustrated magnets

2018 ◽  
Vol 97 (7) ◽  
Author(s):  
Matthias Gohlke ◽  
Gideon Wachtel ◽  
Youhei Yamaji ◽  
Frank Pollmann ◽  
Yong Baek Kim
Keyword(s):  
Quantum Spin ◽  
Spin Liquid ◽  
Frustrated Magnets ◽  
Quantum Spin Liquid

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 Gapless Quantum Spin Liquid in the Triangular System Sr3CuSb2O9

2020 ◽  
Vol 125 (26) ◽  
Author(s):  
S. Kundu ◽  
Aga Shahee ◽  
Atasi Chakraborty ◽  
K. M. Ranjith ◽  
B. Koo ◽  
...  
Keyword(s):  
Quantum Spin ◽  
Spin Liquid ◽  
Triangular System ◽  
Quantum Spin Liquid

scholarly journals Giant phonon anomalies in the proximate Kitaev quantum spin liquid α-RuCl3

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Haoxiang Li ◽  
T. T. Zhang ◽  
A. Said ◽  
G. Fabbris ◽  
D. G. Mazzone ◽  
...  
Keyword(s):  
Acoustic Phonon ◽  
Energy Scale ◽  
Quantum Spin ◽  
Majorana Fermion ◽  
Spin Liquid ◽  
Optical Phonons ◽  
Large Intensity ◽  
Topological Quantum ◽  
Topological State ◽  
Quantum Spin Liquid

AbstractThe Kitaev quantum spin liquid epitomizes an entangled topological state, for which two flavors of fractionalized low-energy excitations are predicted: the itinerant Majorana fermion and the Z2 gauge flux. It was proposed recently that fingerprints of fractional excitations are encoded in the phonon spectra of Kitaev quantum spin liquids through a novel fractional-excitation-phonon coupling. Here, we detect anomalous phonon effects in α-RuCl3 using inelastic X-ray scattering with meV resolution. At high temperature, we discover interlaced optical phonons intercepting a transverse acoustic phonon between 3 and 7 meV. Upon decreasing temperature, the optical phonons display a large intensity enhancement near the Kitaev energy, JK~8 meV, that coincides with a giant acoustic phonon softening near the Z2 gauge flux energy scale. These phonon anomalies signify the coupling of phonon and Kitaev magnetic excitations in α-RuCl3 and demonstrates a proof-of-principle method to detect anomalous excitations in topological quantum materials.

scholarly journals Signatures of a gearwheel quantum spin liquid in a spin- 12 pyrochlore molybdate Heisenberg antiferromagnet

2017 ◽  
Vol 1 (7) ◽  
Author(s):  
Yasir Iqbal ◽  
Tobias Müller ◽  
Kira Riedl ◽  
Johannes Reuther ◽  
Stephan Rachel ◽  
...  
Keyword(s):  
Quantum Spin ◽  
Spin Liquid ◽  
Heisenberg Antiferromagnet ◽  
Quantum Spin Liquid

Electronic structure ofBa3CuSb2O9: A candidate quantum spin liquid compound

2014 ◽  
Vol 89 (8) ◽  
Author(s):  
K. V. Shanavas ◽  
Z. S. Popović ◽  
S. Satpathy
Keyword(s):  
Electronic Structure ◽  
Quantum Spin ◽  
Spin Liquid ◽  
Quantum Spin Liquid
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