Magnon-phonon hybrid excitations are studied theoretically in a two-dimensional antiferromagnet with an easy axis normal to the plane. We show that two magnon bands and one phonon band are intertwined by the magnetoelastic coupling through a nontrivial SU(3) topology, which can be intuitively perceived by identifying a skyrmion structure in the momentum space. Our results are insensitive to lattice details and generally applicable to two-dimensional antiferromagnets. We show this by developing a continuum theory as the long-wavelength approximation to the tight-binding model. The theoretical results can be probed by measuring the thermal Hall conductance as a function of the temperature and the magnetic field. We envision that the magnetoelastic coupling in antiferromagnets can be a promising venue in search of various topological excitations, which cannot be found in magnetic or elastic models alone.

中文翻译：

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二维反铁磁体中磁-声子混合的SU（3）拓扑

理论上，在二维反铁磁体中研究了磁振子-声子混合激发，其易轴垂直于平面。我们表明，通过一个非平凡的SU（3）拓扑结构，磁弹性耦合将两个磁振子带和一个声子带交织在一起，这可以通过识别动量空间中的Skyrmion结构来直观地感知。我们的结果对晶格细节不敏感，通常适用于二维反铁磁体。我们通过发展连续理论作为紧密结合模型的长波长近似来证明这一点。通过测量热霍尔电导随温度和磁场的变化，可以探究理论结果。我们设想，反铁磁体中的磁弹性耦合可能是寻找各种拓扑激发的有前途的场所，