Inplane anisotropy of longitudinal thermal conductivities and weak localization of magnons in a disordered spiral magnet

Abstract

We demonstrate the inplane anisotropy of longitudinal thermal conductivities and the weak localization of magnons in a disordered screw-type spiral magnet on a square lattice. We consider a disordered spin system, described by a spin Hamiltonian for the antiferromagnetic Heisenberg interaction and the Dzyaloshinsky-Moriya interaction with the mean-field type potential of impurities. We derive longitudinal thermal conductivities for the disordered screw-type spiral magnet in the weak-localization regime by using the linear-response theory with the linear-spin-wave approximation and performing perturbation calculations. We show that the inplane longitudinal thermal conductivities are anisotropic due to the Dzyaloshinsky-Moriya interaction. This anisotropy may be useful for experimentally estimating the magnitude of a ratio of the Dzyaloshinsky-Moriya interaction to the Heisenberg interaction. We also show that the main correction term gives a logarithmic suppression with the length scale due to the critical back scattering. This suggests that the weak localization of magnons is ubiquitous for the disordered two-dimensional magnets having global time-reversal symmetry. We finally discuss several implications for further research.

16 pages, 4 figures; published version

References in corpus (7)

• Spontaneous Magnon Decays
• Vector chirality for effective total momentum $J_{\text{eff}}$ in a nonfrustrated Mott insulator: Effects of strong spin-orbit coupling and broken inversion symmetry
• Weak localization of magnons in a disordered two-dimensional antiferromagnet
• Magnon Dispersion and Specific Heat of Chiral Magnets on the Pyrochlore Lattice
• Weak localization of magnons in chiral magnets
• Tunneling between chiral magnets: Spin current generation without external fields
• Negative magneto-thermal-resistance in a disordered two-dimensional antiferromagnet

Cited by in corpus (5)

• Magnon drag induced by magnon-magnon interactions characteristic of noncollinear magnets
• Scattering theory of transport through disordered magnets
• Effects of magnon-magnon interactions in a noncollinear magnet induced by combination of a symmetric and an antisymmetric exchange interaction
• Interband magnon drag in ferrimagnetic insulators
• Momentum Signatures of Site Percolation in Disordered 2D Ferromagnets