Spin-1 antiferromagnetic Heisenberg chains in an external staggered field
Spin-1 antiferromagnetic Heisenberg chains in an external staggered field
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外部交错场中的 Spin-1 反铁磁海森堡链
DOI：
10.1103/physrevb.62.14860
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
M. Roncaglia
中科院分区：
文献类型：
--
作者：
E. Ercolessi;G. Morandi;P. Pieri;M. Roncaglia
本文提出了一个非线性的\ensuremath{\sigma}-模型分析的自旋1反铁磁海森堡链在一个外部的公度交错磁场。本文在简要讨论和推广交错磁化曲线的已有结果后，重点讨论了该模型的绿色函数在树层次上的计算。我们得到精确的结果的基本激发谱，特别是在横向和纵向通道的自旋间隙。结果表明，在横向通道中，谱权由一个磁振子极点耗尽，而在纵向通道中，除了磁振子极点外，还出现了两个磁振子的连续谱，其谱权随外加场的变化而稳定地增加，而磁振子的谱权则相应地减小.两者之间的平衡是由一个总结规则，推导和讨论。与目前的实验和数值状态的最新技术，以及与以前的分析方法进行了详细的比较。
We present in this paper a nonlinear \ensuremath{\sigma}-model analysis of a spin-1 antiferromagnetic Heisenberg chain in an external commensurate staggered magnetic field. After rediscussing briefly and extending previous results for the staggered magnetization curve, the core of the paper is a calculation at the tree level, of the Green functions of the model. We obtain precise results for the elementary excitation spectrum and in particular for the spin gaps in the transverse and longitudinal channels. It is shown that, while the spectral weight in the transverse channel is exhausted by a single magnon pole, in the longitudinal one, besides a magnon pole a two-magnon continuum appears as well whose weight is a steadily increasing function of the applied field, while the weight of the magnon decreases correspondingly. The balance between the two is governed by a sum rule that is derived and discussed. A detailed comparison with the present experimental and numerical state of the art as well as with previous analytical approaches is also made.