| Autor: |
J, Ma, Y, Kamiya, Tao, Hong, H B, Cao, G, Ehlers, W, Tian, C D, Batista, Z L, Dun, H D, Zhou, M, Matsuda |
| Rok vydání: |
2015 |
| Zdroj: |
Physical review letters. 116(8) |
| ISSN: |
1079-7114 |
| Popis: |
We present single-crystal neutron scattering measurements of the spin-1/2 equilateral triangular-lattice antiferromagnet Ba_{3}CoSb_{2}O_{9}. Besides confirming that the Co^{2+} magnetic moments lie in the ab plane for zero magnetic field and then determining all the exchange parameters of the minimal quasi-2D spin Hamiltonian, we provide conclusive experimental evidence of magnon decay through observation of intrinsic line broadening. Through detailed comparisons with the linear and nonlinear spin-wave theories, we also point out that the large-S approximation, which is conventionally employed to predict magnon decay in noncollinear magnets, is inadequate to explain our experimental observation. Thus, our results call for a new theoretical framework for describing excitation spectra in low-dimensional frustrated magnets under strong quantum effects. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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