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arXiv 1407.3402cond-mat.str-elcond-mat.mtrl-sci
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维数在自发磁振子衰变中的作用:易平面铁磁体

Role of dimensionality in spontaneous magnon decay: easy-plane ferromagnet

V. A. Stephanovich, M. E. Zhitomirsky

摘要:

本文计算了横向磁场作用下四方晶格易平面铁磁体中的磁振子寿命。在零温度下,磁振子不稳定,会自发衰变成另外两个磁振子。在这个模型中,我们考虑了维数对自发磁振子衰变的影响。最强的磁振子阻尼被发现在准一维的情况下的动量附近的布里渊区边界。弱链间耦合的符号对磁振子衰变率影响不大。所得的理论结果表明,在准一维铁磁体CsNiF $_3$中实验观察到自发磁振子衰变的可能性。我们还发现了一个有趣的增强磁振子衰减率的三维铁磁体。这种效应只存在于最近邻模型中,并且与双磁振子连续介质中的有效降维有关。

英文摘要:

We calculate magnon lifetime in an easy-plane ferromagnet on a tetragonal lattice in transverse magnetic field. At zero temperature magnons are unstable with respect to spontaneous decay into two other magnons. Varying ratio of intrachain to interchain exchanges in this model we consider the effect of dimensionality on spontaneous magnon decay. The strongest magnon damping is found in the quasi-one-dimensional case for momenta near the Brillouin zone boundary. The sign of a weak interchain coupling has a little effect on the magnon decay rate. The obtained theoretical results suggest possibility of experimental observation of spontaneous magnon decay in a quasi-one-dimensional ferromagnet CsNiF$_3$. We also find an interesting enhancement of the magnon decay rate for a three-dimensional ferromagnet. The effect is present only for the nearest-neighbor model and is related to effective dimensionality reduction in the two-magnon continuum.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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