Spinon mediation of witness spin dynamics in herbertsmithite

Abstract

The kagome lattice of spin-1/2 copper atoms in herbertsmithite is conjectured to sustain a quantum spin liquid state with spinon quasiparticles. Ideally, the kagome crystal planes are each separated by a plane of spinless zinc atoms. However, in real crystals some spin-1/2 copper atoms substitute randomly onto these inter-kagome zinc sites. Here we reconceptualize such 'impurity' atoms as quantum witness spins whose dynamics is designed to probe the spin liquid state. We then introduce spin noise spectroscopy to measure the frequency and temperature dependence of witness spin dynamics, demonstrating that their phenomenology is consistent with extensive interactions between witness spins mediated by propagation of spinons through a quantum spin liquid. Ultimately, a sharp transition occurs at around 260 mK, below which the properties of both spin noise and magnetic susceptibility suggest that the witness spins form a spin glass phase. Among theoretical models considered, we demonstrate that our observations are only consistent with spinon-mediated interactions between witness spins by either a Z2 or U(1) quantum spin liquid, with the former model more closely matching the data. Our work demonstrates that quantum mechanical witness spins may now conceivably be used as a widely applicable probe of quantum spin liquid physics.

arXiv comment55 pages, 5 figures, 8 extended data figures

References in corpus (49)

• Quantum Spin Liquids
• Quantum Spin Liquid States
• Spin Liquid Ground State of the $S=1/2$ Kagome Heisenberg Model
• Fractionalized excitations in the spin liquid state of a kagomé lattice antiferromagnet
• Quantum Spin Liquids
• Spin Dynamics of the Spin-1/2 Kagome Lattice Antiferromagnet ZnCu_3(OH)_6Cl_2
• Projected wavefunction study of Spin-1/2 Heisenberg model on the Kagome lattice
• Herbertsmithite and the Search for the Quantum Spin Liquid
• Quantum magnetism in the paratacamite family: towards an ideal kagome lattice
• Defects in correlated metals and superconductors
• Evidence for a Gapped Spin-Liquid Ground State in a Kagome Heisenberg Antiferromagnet
• RKKY in half-filled bipartite lattices: graphene as an example
• 17O NMR study of the intrinsic magnetic susceptibility and spin dynamics of the quantum kagome antiferromagnet ZnCu3(OH)6Cl2
• Dzyaloshinsky-Moriya Anisotropy in the Spin-1/2 Kagomé Compound ZnCu${}_3$(OH)${}_6$Cl${}_2$
• Quantum spin liquid states in the two dimensional kagome antiferromagnets, ZnxCu4-x(OD)6Cl2
• The magnetic groundstate of an experimental $S=1/2$ kagomé antiferromagnet
• Gapless ground state in the archetypal quantum kagome antiferromagnet ZnCu${}_3$(OH)${}_6$Cl${}_2$
• Correlated impurities and intrinsic spin liquid physics in the kagome material Herbertsmithite
• Z2 spin liquid in S=1/2 Heisenberg model on Kagome lattice: A projective symmetry group study of Schwinger-fermion mean-field states
• Gapped spin liquid with ${\mathbb{Z}}_2$-topological order for kagome Heisenberg model
• Exchange interaction of magnetic impurities in graphene
• ^{63}Cu, ^{35}Cl, and ^{1}H NMR in the S=1/2 Kagomé Lattice ZnCu_{3}(OH)_{6}Cl_{2}
• Dynamic Scaling in the Susceptibility of the Spin-1\2 Kagome Lattice Antiferromagnet Herbertsmithite
• Low temperature magnetization of the S=1/2 kagome antiferromagnet ZnCu_3(OH)_6Cl_2
• The $S=1/2$ Kagome Heisenberg Antiferromagnet Revisited
• Interplay of thermal and quantum spin fluctuations on the kagome lattice
• Refining the Spin Hamiltonian in the Spin-1/2 Kagome Lattice Antiferromagnet ZnCu${}_3$(OH)${}_6$Cl${}_2$ using Single Crystals
• Synthesis and Characterization of Single Crystal Samples of Spin-$1/2$ Kagome Lattice Antiferromagnets in the Zn-Paratacamite Family Zn${}_x$Cu${}_{4-x}$(OH)${}_6$Cl${}_2$
• Magnetic Monopole Noise
• Field-Induced Freezing of a Quantum Spin Liquid on the Kagome Lattice
• Spin Induced Optical Conductivity in the Spin Liquid Candidate Herbertsmithite
• Symmetry Reduction in the Quantum Kagome Antiferromagnet Herbertsmithite
• Emergence of spin singlets with inhomogeneous gaps in the kagome Heisenberg antiferromagnets Zn-barlowite and herbertsmithite
• Local Spin Susceptibility of the S=1/2 Kagome Lattice in ZnCu3(OD)6Cl2
• Heat Transport in Herbertsmithite: Can a Quantum Spin Liquid Survive Disorder?
• RKKY interaction in a doped pseudospin-1 fermion system at finite temperature
• Spin-1/2 kagome compounds: volborthite vs herbertsmithite
• Anomalous magnetic noise in imperfect flat bands in the topological magnet Dy2Ti2O7
• Site-Specific Structure at Multiple Length Scales in Kagome Quantum Spin Liquid Candidates
• The Herbertsmithite Hamiltonian: $\mu$SR measurements on single crystals
• Heat conduction in herbertsmithite: field dependence at the onset of the quantum spin liquid regime
• Spiral Spin Liquid Noise
• Dichotomous Dynamics of Magnetic Monopole Fluids
• Spin liquid mediated RKKY interaction
• Chemo-Structural Disorder in the kagomé spin $S$ = 1/2 systems ZnCu${}_3$(OH)${}_6$Cl${}_2$ and YCu${}_3$(OH)${}_6$Br${}_2$[Br${}_x$(OH)${}_{1-x}$]
• Recent progress in quantum spin liquids, fractional magnetization plateaus, and unconventional superconductivity in kagome lattices
• Power-law dynamics in the spin-liquid kagome lattices SrCr8Ga4O19 and ZnCu3(OH)6Cl2
• Is Herbertsmithite far from an ideal antiferromagnet? Ab-initio answer including in-plane Dzyaloshinskii-Moriya interactions and coupling with extra-plane impurities
• Discovery of Dynamical Heterogeneity in a Supercooled Magnetic Monopole Fluid