Spontaneous magnon decays in planar ferromagnet

Abstract

We predict that spin-waves in an easy-plane ferromagnet have a finite lifetime at zero temperature due to spontaneous decays. In zero field the damping is determined by three-magnon decay processes, whereas decays in the two-particle channel dominate in a transverse magnetic field. Explicit calculations of the magnon damping are performed in the framework of the spin-wave theory for the $XXZ$ square-lattice ferromagnet with an anisotropy parameter $\lambda <1$. In zero magnetic field the decays occur for ${\lambda }^{\ast }<\lambda <1$ with ${\lambda }^{\ast }\approx 1/7$. We also discuss possibility of experimental observation of the predicted effect in a number of ferromagnetic insulators.

6 pages, 6 figures, to appear in Europhysics Letters

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Cited by in corpus (7)

• Spontaneous Magnon Decays
• "Quasi-particle breakdown" in the quasi-one-dimensional Ising ferromagnet CoNb${}_2$O${}_6$
• Diagnosing Fractionalization from the Spin Dynamics of $Z_2$ Spin Liquids on the Kagome Lattice by Quantum Monte Carlo Simulations
• Quantum Damping of Skyrmion Crystal Eigenmodes due to Spontaneous Quasiparticle Decay
• Spontaneous magnon decay in two-dimensional altermagnets
• Role of dimensionality in spontaneous magnon decay: easy-plane ferromagnet
• Field-induced magnon decays in dipolar quantum magnets