Magnetic excitations in quasi-one dimensional helimagnets: Magnon decays and in uence of the inter-chain interactions

Abstract

We present a comprehensive study of the magnetic properties of the long-range ordered quasi-one dimensional $J_1$-$J_2$ systems with a newly developed torque equilibrium spin-wave expansion approach, which can describe the spin Casimir and magnon decay effects in a unified framework. While the framework does not lose the generality, our discussion will be restricted to two representative types of inter-chain coupling systems: $J_3$- or $J_4$-system respectively. In spite of the long-range spiral order, the dynamical properties of these systems turn out to be highly nontrivial due to the incommensurate noncollinear spin configuration and the strong quantum fluctuation effects enhanced by the frustration and low-dimensionality. Both the systems show prominent spin Casimir effects induced by the vacuum fluctuation of the spin waves and related modification of the ordering vector, Lifshitz point's position and sublattice magnetization. Significant and spontaneous magnon decay effects are manifested in the quantum corrections to the excitation spectrum. By adjusting the strength of magnetic anisotropy and varying the approximation scheme, it is revealed that these striking distinct features are quite robust and have deep connection with both the spin Casimir and the magnon decay effects. Thus these special consequences of the inter-chain coupling on the spin wave dynamics may be served as a set of probes for different types of inter-chain couplings in experiments. At last, to guide experimental measurements such as inelastic neutron scattering in realistic materials and complement our theoretical framework, we develop the analytical theory of the dynamical structure factor within the torque equilibrium formulism and provide the explicit results of the quasi-one dimensional $J_1$-$J_2$ systems.

References in corpus (14)

• Vector chiral and multipolar orders in the spin-1/2 frustrated ferromagnetic chain in magnetic field
• Spontaneous Magnon Decays
• Unusual ordered phases of highly frustrated magnets: a review
• Emergent multipolar spin correlations in a fluctuating spiral - The frustrated ferromagnetic S=1/2 Heisenberg chain in a magnetic field
• Evidence of a bond-nematic phase in LiCuVO4
• Magnon Decay in Noncollinear Quantum Antiferromagnets
• Flat spin wave dispersion in a triangular antiferromagnet
• Quantum Selection of Order in an $XXZ$ Antiferromagnet on a Kagomé Lattice
• Search for a spin-nematic phase in the quasi-one-dimensional frustrated magnet LiCuVO${}_4$
• Weakly anisotropic frustrated zigzag spin chain
• Field-induced decay dynamics in square-lattice antiferromagnet
• Influence of an inter-chain coupling on spiral ground-state correlations in frustrated spin-1/2 J1-J2 Heisenberg chains
• Spinons and helimagnons in the frustrated Heisenberg chain
• Dynamical structure factor of quasi-2D antiferromagnet in high fields

Cited by in corpus (6)

• Quantum Damping of Skyrmion Crystal Eigenmodes due to Spontaneous Quasiparticle Decay
• The dynamics of linarite: Observations of magnetic excitations
• Exchange interactions in $d^5$ Kitaev materials: From Na${}_2$IrO${}_3$ to $\alpha$-RuCl${}_3$
• The magnetic phase diagram of the frustrated spin chain compound linarite, PbCuSO${}_4$(OH)${}_2$, as seen by neutron diffraction and ${}^1$H-NMR
• Torque equilibrium spin wave theory of Raman scattering in an anisotropic triangular lattice antiferromagnet with Dzyaloshinskii-Moriya interaction
• Raman scattering study of multimagnon (bi- and tri-magnon) excitations and rotonlike points in the distorted triangular lattice antiferromagnet