scholarly journals Microscopic theory of organic magnetoresistance based on kinetic equations for quantum spin correlations

2020 ◽  
Vol 101 (13) ◽  
Author(s):  
A. V. Shumilin
Keyword(s):  
Kinetic Equations ◽  
Microscopic Theory ◽  
Quantum Spin ◽  
Spin Correlations ◽  
Organic Magnetoresistance

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 A project to measure quantum spin correlations of relativistic electron pairs in Møller scattering

2017 ◽  
Vol 164 ◽  
pp. 01004
Author(s):  
Jacek Ciborowski ◽  
Paweł Caban ◽  
Michał Drągowski ◽  
Joachim Enders ◽  
Yuliya Fritzsche ◽  
...  
Keyword(s):  
Relativistic Electron ◽  
Quantum Spin ◽  
Electron Pairs ◽  
Spin Correlations ◽  
Moller Scattering

scholarly journals Magnetic field-induced intermediate quantum spin liquid with a spinon Fermi surface

2019 ◽  
Vol 116 (25) ◽  
pp. 12199-12203 ◽  
Author(s):  
Niravkumar D. Patel ◽  
Nandini Trivedi
Keyword(s):  
Magnetic Field ◽  
Fermi Surface ◽  
Intermediate Phase ◽  
Quantum Spin ◽  
Spin Liquid ◽  
Spin Correlations ◽  
Density Matrix Renormalization ◽  
Static Spin ◽  
Kitaev Model ◽  
Quantum Spin Liquid

The Kitaev model with an applied magnetic field in the H∥[111] direction shows two transitions: from a nonabelian gapped quantum spin liquid (QSL) to a gapless QSL at Hc1≃0.2K and a second transition at a higher field Hc2≃0.35K to a gapped partially polarized phase, where K is the strength of the Kitaev exchange interaction. We identify the intermediate phase to be a gapless U(1) QSL and determine the spin structure function S(k) and the Fermi surface ϵFS(k) of the gapless spinons using the density matrix renormalization group (DMRG) method for large honeycomb clusters. Further calculations of static spin-spin correlations, magnetization, spin susceptibility, and finite temperature-specific heat and entropy corroborate the gapped and gapless nature of the different field-dependent phases. In the intermediate phase, the spin-spin correlations decay as a power law with distance, indicative of a gapless phase.

scholarly journals Observation of plaquette fluctuations in the spin-1/2 honeycomb lattice

2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Christian Wessler ◽  
Bertrand Roessli ◽  
Karl W. Krämer ◽  
Bernard Delley ◽  
Oliver Waldmann ◽  
...  
Keyword(s):  
Quantum Critical Point ◽  
Spin Correlation ◽  
Quantum Spin ◽  
Honeycomb Lattice ◽  
Spin Liquids ◽  
Spin Correlations ◽  
Quantum Spin Liquids ◽  
Dynamic Spin ◽  
New Perspective ◽  
The Continuum

AbstractQuantum spin liquids are materials that feature quantum entangled spin correlations and avoid magnetic long-range order at T = 0 K. Particularly interesting are two-dimensional honeycomb spin lattices where a plethora of exotic quantum spin liquids have been predicted. Here, we experimentally study an effective S = 1/2 Heisenberg honeycomb lattice with competing nearest and next-nearest-neighbour interactions. We demonstrate that YbBr3 avoids order down to at least T = 100 mK and features a dynamic spin–spin correlation function with broad continuum scattering typical of quantum spin liquids near a quantum critical point. The continuum in the spin spectrum is consistent with plaquette type fluctuations predicted by theory. Our study is the experimental demonstration that strong quantum fluctuations can exist on the honeycomb lattice even in the absence of Kitaev-type interactions, and opens a new perspective on quantum spin liquids.

scholarly journals Strong Quantum Spin Correlations Observed in Atomic Spin Mixing

2011 ◽  
Vol 107 (21) ◽  
Author(s):  
Eva M. Bookjans ◽  
Christopher D. Hamley ◽  
Michael S. Chapman
Keyword(s):  
Quantum Spin ◽  
Spin Correlations ◽  
Atomic Spin

Zero-temperature properties of quantum spin models on the triangular lattice II: the antiferromagnet

1987 ◽  
Vol 65 (1) ◽  
pp. 76-81 ◽  
Author(s):  
S. Fujiki ◽  
D. D. Betts
Keyword(s):  
Triangular Lattice ◽  
State Energy ◽  
Spin Correlation ◽  
Quantum Spin ◽  
Transverse Spin ◽  
Nearest Neighbour ◽  
Spin Correlations ◽  
Infinite Lattice ◽  
Longitudinal Correlation ◽  
Quantum Spin Models

The calculation of two- and four-spin correlations of the [Formula: see text] antiferromagnet has been extended to an N = 21 site triangular lattice. By fitting a quadratic in 1/N to the nearest neighbour transverse spin correlations, we have estimated the ground-state energy per bond on the infinite lattice to be E0/3NJ = −0.2716 ± 0.005. The nearest neighbour longitudinal correlation is estimated to be [Formula: see text]. A short-range order parameter, the chirality, is defined and estimated for the infinite lattice. From the N dependence of the three sublattice or helical magnetization, the spin correlation is conjectured to decay algebraically as [Formula: see text].

scholarly journals Quantum Spin Correlations in an Organometallic Alternating-Sign Chain

2007 ◽  
Vol 99 (8) ◽  
Author(s):  
M. B. Stone ◽  
W. Tian ◽  
M. D. Lumsden ◽  
G. E. Granroth ◽  
D. Mandrus ◽  
...  
Keyword(s):  
Quantum Spin ◽  
Spin Correlations
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