Field induced spontaneous quasiparticle decay and renormalization of quasiparticle dispersion in a quantum antiferromagnet

Abstract

The notion of a quasiparticle, such as a phonon, a roton, or a magnon, is used in modern condensed matter physics to describe an elementary collective excitation. The intrinsic zero-temperature magnon damping in quantum spin systems can be driven by the interaction of the one-magnon states and multi-magnon continuum. However, detailed experimental studies on this quantum many-body effect induced by an applied magnetic field are rare. Here we present a high-resolution neutron scattering study in high fields on an S=1/2 antiferromagnet C9H18N2CuBr4. Compared with the non-interacting linear spin-wave theory, our results demonstrate a variety of phenomena including field-induced renormalization of one-magnon dispersion, spontaneous magnon decay observed via intrinsic linewidth broadening, unusual non-Lorentzian two-peak structure in the excitation spectra, and a dramatic shift of spectral weight from one-magnon state to the two-magnon continuum.

8 pages, 6 figures, some typos were corrected in the revised version

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• Spontaneous Magnon Decays
• Quantum Magnets under Pressure: Controlling Elementary Excitations in TlCuCl3
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• Decay of quasiparticles in quantum spin liquids
• Quantum Heisenberg antiferromagnets in a uniform magnetic field: nonanalytic magnetic field dependence of the magnon spectrum
• Numerical evidence for unstable magnons at high fields in the Heisenberg antiferromagnet on the square lattice
• Effect of pressure on the quantum spin ladder material IPA-CuCl3
• Magnetic ordering induced by interladder coupling in the spin-1/2 Heisenberg two-leg ladder antiferromagnet C${}_9$H${}_{18}$N${}_2$CuBr${}_4$
• Dynamical structure factor of quasi-2D antiferromagnet in high fields
• Neutron scattering study of a quasi-2D spin-1/2 dimer system Piperazinium Hexachlorodicuprate under hydrostatic pressure

Cited by in corpus (18)

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• Strong quantum interactions prevent quasiparticle decay
• Direct observation of the Higgs amplitude mode in a two-dimensional quantum antiferromagnet near the quantum critical point
• Magnon damping in the zigzag phase of the Kitaev-Heisenberg-$\Gamma$ model on a honeycomb lattice
• Bond-dependent anisotropy and magnon decay in cobalt-based Kitaev triangular antiferromagnet
• Magnon interactions in the frustrated pyrochlore ferromagnet Yb${}_2$Ti${}_2$O${}_7$
• Quantum Damping of Skyrmion Crystal Eigenmodes due to Spontaneous Quasiparticle Decay
• Magnetic Excitations in the Ground State of $\mathrm{Y}{\mathrm{b}}_2\mathrm{T}{\mathrm{i}}_2{\mathrm{O}}_7$
• Instabilities of heavy magnons in an anisotropic magnet
• Decay and renormalization of a longitudinal mode in a quasi-two-dimensional antiferromagnet
• Topological Hybrids of Magnons and Magnon Bound Pairs
• Evidence for pressure induced unconventional quantum criticality in the coupled spin ladder antiferromagnet C${}_9$H${}_{18}$N${}_2$CuBr${}_4$
• The Higgs Mode of Planar Coupled Spin-Ladders and its Observation in C${}_9$H${}_{18}$N${}_2$CuBr${}_4$
• Magnetic excitations in magnetization plateaux of a frustrated spin ladder
• Spectral characteristics of the antiferromagnetic spin-1/2 Heisenberg model on the square lattice in a magnetic field
• Pressure-tuned quantum criticality in the large-$D$ antiferromagnet DTN
• Interacting triplons in frustrated spin ladders: Binding and decay in BiCu${}_2$PO${}_6$
• High-throughput search for topological magnon materials