Dynamics of a bond-disordered $S=1$ quantum magnet near $z=1$ criticality

Abstract

Neutron scattering is used to study NiCl${}_{2-2x}$Br${}_{2x}\cdot$4SC(NH${}_2$)${}_2$, $x=0.06$, a bond-disordered modification of the well-known gapped $S=1$ antiferromagnetic quantum spin system NiCl${}_2\cdot$4SC(NH${}_2$)${}_2$. The magnetic excitation spectrum throughout Brillouin zone is mapped out at $T=60$ mK using high-resolution time-of-flight spectroscopy. It is found that the dispersion of spin excitation is renormalized, as compared to that in the parent compound. The lifetime of excitations near the bottom of the band is substantially decreased. No localized states are found below the gap energy $\Delta \simeq 0.2$ meV. At the same time, localized zero wave vector states are detected above the top of the band. The results are consistent with a more or less continuous random distribution of bond strengths, and a discrete, possibly bimodal, distribution of single-ion anisotropies in the disordered material.

arXiv comment11 pages, 10 figures, 3 tables

References in corpus (30)

• Quantum magnetism and criticality
• Rare region effects at classical, quantum, and non-equilibrium phase transitions
• Quantum Criticality: competing ground states in low dimensions
• Bose-Einstein Condensation of S = 1 Ni spin degrees of freedom in NiCl2-4SC(NH2)2
• Spin-Vacancy-Induced Long-Range Order in a New Haldane-Gap Antiferromagnet
• Bose glass and Mott glass of quasiparticles in a doped quantum magnet
• Magnetic Excitations in the Spin-1 Anisotropic Heisenberg Antiferromagnetic Chain System NiCl${}_2$-4SC(NH${}_2$)${}_2$
• Continuum in the spin excitation spectrum of a Haldane chain, observed by neutron scattering in CsNiCl3
• A direct measurement of the Bose-Einstein Condensation universality class in NiCl${}_2$-4SC(NH${}_2$)${}_2$ at ultra-low temperatures
• Quenching the Haldane gap in spin-1 Heisenberg antiferromagnets
• Dirty-boson physics with magnetic insulators
• Random Bond Effect in the Quantum Spin System (Tl${}_{1-x}$K${}_x$)CuCl${}_3$
• Quantum-critical spin dynamics in quasi-one-dimensional antiferromagnets
• Phase Diagram and Magnetic Excitations of Anisotropic Spin-One Magnets
• Field-induced criticality in a gapped quantum magnet with bond disorder
• Characterizing the Haldane phase in quasi-one-dimensional spin-1 Heisenberg antiferromagnets
• Multi-particle States in Spin-1 Chain System CsNiCl3
• Spin Dynamics of $NiC{l}_2-4SC(N{H}_2{)}_2$ in the Field-Induced Ordered Phase
• Excitation spectra of disordered dimer magnets near quantum criticality
• Criticality in a disordered quantum antiferromagnet by neutron diffraction
• Crystals for neutron scattering studies of quantum magnetism
• Novel approach to description of quantum magnets with large singe-ion easy-plane anisotropy
• Disorder instability of the magnon condensate in a frustrated spin ladder
• Excitations in a quantum spin liquid with random bonds
• Critical exponents and intrinsic broadening of the field-induced transition in NiCl${}_2$$\cdot$4SC(NH${}_2$)${}_2$
• Field-concentration phase diagram of a quantum spin liquid with bond defects
• Bond Randomness Induced Magnon Decoherence in a Spin-1/2 Ladder Compound
• Localized and propagating excitations in gapped phases of spin systems with bond disorder
• The tunable quantum spin ladder Cu(Qnx)(Cl${}_{(1-x)}$Br${}_x$)${}_2$
• Formation of gapless triplets in the bond-doped spin-gap antiferromagnet (C${}_4$H${}_{12}$N${}_2$)(Cu${}_2$Cl${}_6$)

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• Quantum-critical properties of the one- and two-dimensional random transverse-field Ising model from large-scale quantum Monte Carlo simulations
• Self-consistent T-matrix approach to gap renormalization in quantum magnets with bond disorder
• Microwave dynamics of pure and doped anisotropic S=1 chain antiferromagnet NiCl2-4SC(NH2)2
• Magnon spectrum and electron spin resonance in antiferromagnet with large single-ion easy plane anisotropy
• Finite-temperature dynamics and the role of disorder in nearly critical Ni(Cl${}_{1-x}$Br${}_x$)${}_2$$\cdot$4SC(NH${}_2$)${}_2$
• Magnetodipolar interaction and quasiparticles delocalization in disordered quantum magnets