RVB signatures in the spin dynamics of the square-lattice Heisenberg antiferromagnet
RVB signatures in the spin dynamics of the square-lattice Heisenberg antiferromagnet
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DOI：
10.1209/0295-5075/113/57001
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发表时间：
2016-01
期刊：
影响因子：
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通讯作者：
E. Ghioldi;Matías G. Gonzalez;L. Manuel;A. E. Trumper
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文献类型：
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作者：
E. Ghioldi;Matías G. Gonzalez;L. Manuel;A. E. Trumper
我们通过改进的平均场施温格玻色子计算研究了方晶格自旋海森堡反铁磁体的自旋动力学。通过识别基态的长程 Néel 和类 RVB 分量，我们对平均场磁激发提出了有根据的猜测，该猜测由局部和键自旋翻转的线性组合组成，以计算动态结构因子。我们的主要结果是，当以满足相应求和规则的方式优化磁激励时，我们恢复了实验光谱的低能和高能谱权重特征。特别是，在最近的非弹性中子散射实验中发现的异常谱权损耗可归因于基态RVB分量的三重键激发的干扰。我们得出的结论是，施温格玻色子理论似乎是充分解释方晶格海森堡反铁磁体动态特性的良好候选者。
We investigate the spin dynamics of the square-lattice spin- Heisenberg antiferromagnet by means of an improved mean-field Schwinger boson calculation. By identifying both, the long-range Néel and the RVB-like components of the ground state, we propose an educated guess for the mean-field magnetic excitation consisting on a linear combination of local and bond spin flips to compute the dynamical structure factor. Our main result is that when this magnetic excitation is optimized in such a way that the corresponding sum rule is fulfilled, we recover the low- and high-energy spectral weight features of the experimental spectrum. In particular, the anomalous spectral weight depletion at found in recent inelastic neutron scattering experiments can be attributed to the interference of the triplet bond excitations of the RVB component of the ground state. We conclude that the Schwinger boson theory seems to be a good candidate to adequately interpret the dynamic properties of the square-lattice Heisenberg antiferromagnet.